diff --git a/CHANGELOG.md b/CHANGELOG.md
index e2d4bd74..2c2142bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 - every command that takes a team now accepts its key, name, or UUID, resolved through one shared lookup: `team states`, `team members`, `team delete`, `label list/create/delete --team`, `cycle list/view --team`, `project list/create/update --team`, `document list/create/update --team`, and `issue query/mine/create/update --team`. Keys stay canonical and win over a same-spelled name; an unknown team errors with the list of valid keys instead of an empty result or a raw API error. Previously only keys worked, which is why [#276](https://github.com/schpet/linear-cli/issues/276) asked for `team list --json` as a name-to-key lookup
 - `issue query --state` and `issue mine --state` accept a workflow state name or ID as well as the six state types, looked up within the queried team scope (all teams under `--all-teams`, where a name matches every team's same-named state). An unknown name errors and lists the scope's states, and types and names can be mixed
 - `project update --content <markdown>` and `--content-file <path>` replace a project's long-form overview body, matching the flags `project create` already had. Previously the only way to change the body after creation was a hand-written `projectUpdate` mutation through `linear api`
+- `issue update --clear-due-date`, `--clear-estimate`, `--clear-parent`, `--clear-project`, and `--clear-milestone`, plus `project update --clear-lead`, `--clear-start-date`, and `--clear-target-date`, to remove a value the way `--unassign` and `--clear-cycle` already do. Each sends an explicit `null` to Linear and errors when combined with its set flag; `--clear-project` also rejects `--milestone`, since a milestone belongs to the project being removed. Previously these fields could only be changed, never cleared: cliffy treats `--due-date ""` as a missing value
 - `--json` (`-j`) on `team list`, `cycle list`, `cycle view`, `milestone list`, `milestone view`, and `project view`, the last read commands without machine-readable output. List commands emit the same `{ nodes, pageInfo }` connection shape as the other list commands, after the same filtering and ordering as the table; view commands emit the GraphQL object as fetched, including every issue rather than the ten-item preview, and `milestone view --all --json` includes every page. (A 2.0.0 entry claimed `cycle list --json`; that change never actually landed.) ([#276](https://github.com/schpet/linear-cli/issues/276); thanks @lakardion)
 
 ### Fixed
diff --git a/README.md b/README.md
index f92884cb..6e62c1f0 100644
--- a/README.md
+++ b/README.md
@@ -145,6 +145,7 @@ linear issue create -t "title" -d "description"  # create with flags
 linear issue create --project "My Project" --milestone "Phase 1"  # create with milestone
 linear issue update    # update an issue (interactive prompts)
 linear issue update ENG-123 --milestone "Phase 2"  # set milestone on existing issue
+linear issue update ENG-123 --clear-due-date --clear-parent  # remove values (also --clear-estimate, --clear-project, --clear-milestone, --clear-cycle, --unassign)
 linear issue delete    # delete an issue
 linear issue comment list          # list comments on current issue
 linear issue comment add           # add a comment to current issue
@@ -202,6 +203,7 @@ linear project view <projectId> --json  # project details as JSON
 linear project create --name "API v2" --team ENG --content-file overview.md
 linear project create --name "Mobile launch" --team APP --priority high --label Launch --member jane@example.com
 linear project update <projectId> --content-file overview.md  # replace the project's overview body
+linear project update <projectId> --clear-lead --clear-target-date  # remove values (also --clear-start-date)
 linear project comment list <project>                         # list the project's discussion thread (UUID, slug, or name)
 linear project comment add <project> --body "Kickoff Monday"  # comment on a project
 linear project comment add <project> --body "+1" --reply-to <commentId>  # reply in a thread
diff --git a/docs/usage.md b/docs/usage.md
index 7fbf3c64..2982021b 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -180,6 +180,21 @@ linear issue update TEAM-123 --remove-label sprint-42 --add-label sprint-43
 linear issue update TEAM-123 --label bug --label frontend
 ```
 
+clear optional fields (each `--clear-*` flag conflicts with its set flag):
+
+```bash
+# Remove the due date, estimate, parent, project, or milestone
+linear issue update TEAM-123 --clear-due-date
+linear issue update TEAM-123 --clear-estimate --clear-parent
+linear issue update TEAM-123 --clear-project --clear-milestone
+
+# Move to another project and detach the milestone in one update
+linear issue update TEAM-123 --project "Mobile App" --clear-milestone
+
+# Assignee and cycle have their own clearing flags
+linear issue update TEAM-123 --unassign --clear-cycle
+```
+
 #### other issue commands
 
 get issue id from current git branch:
@@ -299,6 +314,9 @@ linear project update PROJECT-ID --description "Short summary" --content "## Ove
 
 # Replace the overview body from a markdown file
 linear project update PROJECT-ID --content-file overview.md
+
+# Remove the lead, start date, or target date (each conflicts with its set flag)
+linear project update PROJECT-ID --clear-lead --clear-start-date --clear-target-date
 ```
 
 #### list projects
diff --git a/skills/linear-cli/references/issue.md b/skills/linear-cli/references/issue.md
index 0defd226..d3453c92 100644
--- a/skills/linear-cli/references/issue.md
+++ b/skills/linear-cli/references/issue.md
@@ -598,10 +598,13 @@ Options:
   --workspace         <slug>         - Target workspace (uses credentials)                                              
   -a, --assignee      <assignee>     - Assign the issue to 'self' or someone (by username or name)                      
   --unassign                         - Clear the issue's assignee (cannot be combined with --assignee)                  
-  --due-date          <dueDate>      - Due date of the issue                                                            
-  --parent            <parent>       - Parent issue (if any) as a team_number code                                      
+  --due-date          <dueDate>      - Due date of the issue. Use --clear-due-date to remove it                         
+  --clear-due-date                   - Remove the issue's due date (cannot be combined with --due-date)                 
+  --parent            <parent>       - Parent issue (if any) as a team_number code. Use --clear-parent to remove it     
+  --clear-parent                     - Remove the issue's parent (cannot be combined with --parent)                     
   -p, --priority      <priority>     - Priority of the issue (1-4, descending priority)                                 
-  --estimate          <estimate>     - Points estimate of the issue                                                     
+  --estimate          <estimate>     - Points estimate of the issue. Use --clear-estimate to remove it                  
+  --clear-estimate                   - Remove the issue's estimate (cannot be combined with --estimate)                 
   -d, --description   <description>  - Description of the issue                                                         
   --description-file  <path>         - Read description from a file (preferred for markdown content)                    
   -l, --label         <label>        - Issue label associated with the issue; replaces the issue's entire label set.    
@@ -610,10 +613,15 @@ Options:
   --remove-label      <label>        - Remove a label from the issue, keeping its other labels (does not delete the     
                                        label from the team). May be repeated.                                           
   --team              <team>         - Team (key, name, or ID) to move the issue to                                     
-  --project           <project>      - Project to assign the issue to (UUID, slug ID, or name)                          
+  --project           <project>      - Project to assign the issue to (UUID, slug ID, or name). Use --clear-project to  
+                                       remove it                                                                        
+  --clear-project                    - Remove the issue from its project (cannot be combined with --project or          
+                                       --milestone)                                                                     
   -s, --state         <state>        - Workflow state for the issue (by name or type)                                   
   --milestone         <milestone>    - Project milestone (UUID, or name when --project is set or the issue already has  
-                                       a project)                                                                       
+                                       a project). Use --clear-milestone to remove it                                   
+  --clear-milestone                  - Remove the issue from its project milestone (cannot be combined with             
+                                       --milestone)                                                                     
   --cycle             <cycle>        - Cycle name, number, 'active'/'now', 'next', 'previous', or a relative offset     
                                        like +1 (use --cycle=-1 for negatives). Use --clear-cycle to remove the issue    
                                        from its cycle                                                                   
diff --git a/skills/linear-cli/references/project.md b/skills/linear-cli/references/project.md
index e75a5fd8..78715273 100644
--- a/skills/linear-cli/references/project.md
+++ b/skills/linear-cli/references/project.md
@@ -200,9 +200,12 @@ Options:
   --content               <markdown>     - Project overview markdown                                                   
   --content-file          <path>         - Read project overview markdown from a file                                  
   -s, --status            <status>       - Status (planned, started, paused, completed, canceled, backlog)             
-  -l, --lead              <lead>         - Project lead (username, email, or @me)                                      
-  --start-date            <startDate>    - Start date (YYYY-MM-DD)                                                     
-  --target-date           <targetDate>   - Target date (YYYY-MM-DD)                                                    
+  -l, --lead              <lead>         - Project lead (username, email, or @me). Use --clear-lead to remove it       
+  --clear-lead                           - Remove the project's lead (cannot be combined with --lead)                  
+  --start-date            <startDate>    - Start date (YYYY-MM-DD). Use --clear-start-date to remove it                
+  --clear-start-date                     - Remove the project's start date (cannot be combined with --start-date)      
+  --target-date           <targetDate>   - Target date (YYYY-MM-DD). Use --clear-target-date to remove it              
+  --clear-target-date                    - Remove the project's target date (cannot be combined with --target-date)    
   -t, --team              <team>         - Team key, name, or ID (can be repeated for multiple teams)                  
   --label                 <label>        - Replace the project's labels. May be repeated to set multiple labels.
 ```
diff --git a/src/commands/issue/issue-update.ts b/src/commands/issue/issue-update.ts
index c538e2d5..77afceb3 100644
--- a/src/commands/issue/issue-update.ts
+++ b/src/commands/issue/issue-update.ts
@@ -40,11 +40,19 @@ export const updateCommand = new Command()
   )
   .option(
     "--due-date <dueDate:string>",
-    "Due date of the issue",
+    "Due date of the issue. Use --clear-due-date to remove it",
+  )
+  .option(
+    "--clear-due-date",
+    "Remove the issue's due date (cannot be combined with --due-date)",
   )
   .option(
     "--parent <parent:string>",
-    "Parent issue (if any) as a team_number code",
+    "Parent issue (if any) as a team_number code. Use --clear-parent to remove it",
+  )
+  .option(
+    "--clear-parent",
+    "Remove the issue's parent (cannot be combined with --parent)",
   )
   .option(
     "-p, --priority <priority:number>",
@@ -52,7 +60,11 @@ export const updateCommand = new Command()
   )
   .option(
     "--estimate <estimate:number>",
-    "Points estimate of the issue",
+    "Points estimate of the issue. Use --clear-estimate to remove it",
+  )
+  .option(
+    "--clear-estimate",
+    "Remove the issue's estimate (cannot be combined with --estimate)",
   )
   .option(
     "-d, --description <description:string>",
@@ -83,7 +95,11 @@ export const updateCommand = new Command()
   )
   .option(
     "--project <project:string>",
-    "Project to assign the issue to (UUID, slug ID, or name)",
+    "Project to assign the issue to (UUID, slug ID, or name). Use --clear-project to remove it",
+  )
+  .option(
+    "--clear-project",
+    "Remove the issue from its project (cannot be combined with --project or --milestone)",
   )
   .option(
     "-s, --state <state:string>",
@@ -91,7 +107,11 @@ export const updateCommand = new Command()
   )
   .option(
     "--milestone <milestone:string>",
-    "Project milestone (UUID, or name when --project is set or the issue already has a project)",
+    "Project milestone (UUID, or name when --project is set or the issue already has a project). Use --clear-milestone to remove it",
+  )
+  .option(
+    "--clear-milestone",
+    "Remove the issue from its project milestone (cannot be combined with --milestone)",
   )
   .option(
     "--cycle <cycle:string>",
@@ -109,9 +129,12 @@ export const updateCommand = new Command()
         unassign,
         clearCycle,
         dueDate,
+        clearDueDate,
         parent,
+        clearParent,
         priority,
         estimate,
+        clearEstimate,
         description,
         descriptionFile,
         label: labels,
@@ -119,8 +142,10 @@ export const updateCommand = new Command()
         removeLabel,
         team,
         project,
+        clearProject,
         state,
         milestone,
+        clearMilestone,
         cycle,
         title,
       },
@@ -147,6 +172,70 @@ export const updateCommand = new Command()
           )
         }
 
+        if (clearDueDate && dueDate != null) {
+          throw new ValidationError(
+            "Cannot specify both --due-date and --clear-due-date",
+            {
+              suggestion:
+                "Use --due-date <date> to set a due date, or --clear-due-date on its own to remove it.",
+            },
+          )
+        }
+
+        // `!= null`, not truthiness: `--estimate 0` is an explicit value.
+        if (clearEstimate && estimate != null) {
+          throw new ValidationError(
+            "Cannot specify both --estimate and --clear-estimate",
+            {
+              suggestion:
+                "Use --estimate <points> to set an estimate, or --clear-estimate on its own to remove it.",
+            },
+          )
+        }
+
+        if (clearParent && parent != null) {
+          throw new ValidationError(
+            "Cannot specify both --parent and --clear-parent",
+            {
+              suggestion:
+                "Use --parent <issue> to set a parent, or --clear-parent on its own to remove it.",
+            },
+          )
+        }
+
+        if (clearProject && project != null) {
+          throw new ValidationError(
+            "Cannot specify both --project and --clear-project",
+            {
+              suggestion:
+                "Use --project <project> to set a project, or --clear-project on its own to remove it.",
+            },
+          )
+        }
+
+        // A milestone belongs to a project, so keeping one while removing the
+        // project is contradictory (and a milestone name would resolve against
+        // the project being removed).
+        if (clearProject && milestone != null) {
+          throw new ValidationError(
+            "Cannot specify --milestone while clearing the issue's project",
+            {
+              suggestion:
+                "Drop --milestone, or replace it with --clear-milestone to remove both the project and the milestone.",
+            },
+          )
+        }
+
+        if (clearMilestone && milestone != null) {
+          throw new ValidationError(
+            "Cannot specify both --milestone and --clear-milestone",
+            {
+              suggestion:
+                "Use --milestone <milestone> to set a milestone, or --clear-milestone on its own to remove it.",
+            },
+          )
+        }
+
         if (labels != null && (addLabel != null || removeLabel != null)) {
           throw new ValidationError(
             "Cannot combine --label with --add-label or --remove-label",
@@ -329,8 +418,14 @@ export const updateCommand = new Command()
         } else if (assigneeId != null) {
           input.assigneeId = assigneeId
         }
-        if (dueDate !== undefined) input.dueDate = dueDate
-        if (parent !== undefined) {
+        if (clearDueDate) {
+          input.dueDate = null
+        } else if (dueDate !== undefined) {
+          input.dueDate = dueDate
+        }
+        if (clearParent) {
+          input.parentId = null
+        } else if (parent !== undefined) {
           const parentIdentifier = await getIssueIdentifier(parent)
           if (!parentIdentifier) {
             throw new ValidationError(
@@ -344,7 +439,11 @@ export const updateCommand = new Command()
           input.parentId = parentId
         }
         if (priority !== undefined) input.priority = priority
-        if (estimate !== undefined) input.estimate = estimate
+        if (clearEstimate) {
+          input.estimate = null
+        } else if (estimate !== undefined) {
+          input.estimate = estimate
+        }
         if (finalDescription !== undefined) input.description = finalDescription
         if (labels != null) {
           input.labelIds = labelIds
@@ -353,8 +452,14 @@ export const updateCommand = new Command()
           if (removeLabel != null) input.removedLabelIds = removedLabelIds
         }
         if (teamId !== undefined) input.teamId = teamId
-        if (projectId !== undefined) input.projectId = projectId
-        if (projectMilestoneId !== undefined) {
+        if (clearProject) {
+          input.projectId = null
+        } else if (projectId !== undefined) {
+          input.projectId = projectId
+        }
+        if (clearMilestone) {
+          input.projectMilestoneId = null
+        } else if (projectMilestoneId !== undefined) {
           input.projectMilestoneId = projectMilestoneId
         }
         if (clearCycle) {
diff --git a/src/commands/project/project-update.ts b/src/commands/project/project-update.ts
index e9cfc9c0..3cfb7f49 100644
--- a/src/commands/project/project-update.ts
+++ b/src/commands/project/project-update.ts
@@ -82,9 +82,30 @@ export const updateCommand = new Command()
     "-s, --status <status:string>",
     "Status (planned, started, paused, completed, canceled, backlog)",
   )
-  .option("-l, --lead <lead:string>", "Project lead (username, email, or @me)")
-  .option("--start-date <startDate:string>", "Start date (YYYY-MM-DD)")
-  .option("--target-date <targetDate:string>", "Target date (YYYY-MM-DD)")
+  .option(
+    "-l, --lead <lead:string>",
+    "Project lead (username, email, or @me). Use --clear-lead to remove it",
+  )
+  .option(
+    "--clear-lead",
+    "Remove the project's lead (cannot be combined with --lead)",
+  )
+  .option(
+    "--start-date <startDate:string>",
+    "Start date (YYYY-MM-DD). Use --clear-start-date to remove it",
+  )
+  .option(
+    "--clear-start-date",
+    "Remove the project's start date (cannot be combined with --start-date)",
+  )
+  .option(
+    "--target-date <targetDate:string>",
+    "Target date (YYYY-MM-DD). Use --clear-target-date to remove it",
+  )
+  .option(
+    "--clear-target-date",
+    "Remove the project's target date (cannot be combined with --target-date)",
+  )
   .option(
     "-t, --team <team:string>",
     "Team key, name, or ID (can be repeated for multiple teams)",
@@ -105,8 +126,11 @@ export const updateCommand = new Command()
         contentFile,
         status,
         lead,
+        clearLead,
         startDate,
+        clearStartDate,
         targetDate,
+        clearTargetDate,
         team: teams,
         label: labels,
       },
@@ -122,14 +146,45 @@ export const updateCommand = new Command()
         if (
           !name && description == null && descriptionFile == null &&
           content == null && contentFile == null && !status &&
-          !lead && !startDate && !targetDate &&
+          !lead && !clearLead && !startDate && !clearStartDate &&
+          !targetDate && !clearTargetDate &&
           (!teams || teams.length === 0) && (!labels || labels.length === 0)
         ) {
           throw new ValidationError(
             "At least one update option must be provided",
             {
               suggestion:
-                "Use --name, --description, --description-file, --content, --content-file, --status, --lead, --start-date, --target-date, --team, or --label",
+                "Use --name, --description, --description-file, --content, --content-file, --status, --lead, --clear-lead, --start-date, --clear-start-date, --target-date, --clear-target-date, --team, or --label",
+            },
+          )
+        }
+
+        if (clearLead && lead != null) {
+          throw new ValidationError(
+            "Cannot specify both --lead and --clear-lead",
+            {
+              suggestion:
+                "Use --lead <user> to set a lead, or --clear-lead on its own to remove it.",
+            },
+          )
+        }
+
+        if (clearStartDate && startDate != null) {
+          throw new ValidationError(
+            "Cannot specify both --start-date and --clear-start-date",
+            {
+              suggestion:
+                "Use --start-date <date> to set a start date, or --clear-start-date on its own to remove it.",
+            },
+          )
+        }
+
+        if (clearTargetDate && targetDate != null) {
+          throw new ValidationError(
+            "Cannot specify both --target-date and --clear-target-date",
+            {
+              suggestion:
+                "Use --target-date <date> to set a target date, or --clear-target-date on its own to remove it.",
             },
           )
         }
@@ -170,8 +225,18 @@ export const updateCommand = new Command()
         if (name) input.name = name
         if (resolvedDescription != null) input.description = resolvedDescription
         if (resolvedContent != null) input.content = resolvedContent
-        if (startDate) input.startDate = startDate
-        if (targetDate) input.targetDate = targetDate
+        // Clearing a field requires an explicit flag; never set a field to
+        // null implicitly.
+        if (clearStartDate) {
+          input.startDate = null
+        } else if (startDate) {
+          input.startDate = startDate
+        }
+        if (clearTargetDate) {
+          input.targetDate = null
+        } else if (targetDate) {
+          input.targetDate = targetDate
+        }
 
         if (status) {
           const statusLower = status.toLowerCase()
@@ -195,7 +260,9 @@ export const updateCommand = new Command()
           input.statusId = matchingStatus.id
         }
 
-        if (lead) {
+        if (clearLead) {
+          input.leadId = null
+        } else if (lead) {
           const leadId = await lookupUserId(lead)
           if (!leadId) {
             spinner?.stop()
diff --git a/test/commands/issue/__snapshots__/issue-update.test.ts.snap b/test/commands/issue/__snapshots__/issue-update.test.ts.snap
index 325c66ef..7e1cc90a 100644
--- a/test/commands/issue/__snapshots__/issue-update.test.ts.snap
+++ b/test/commands/issue/__snapshots__/issue-update.test.ts.snap
@@ -19,10 +19,13 @@ Options:
   -h, --help                         - Show this help.                                                                  
   -a, --assignee      <assignee>     - Assign the issue to 'self' or someone (by username or name)                      
   --unassign                         - Clear the issue's assignee (cannot be combined with --assignee)                  
-  --due-date          <dueDate>      - Due date of the issue                                                            
-  --parent            <parent>       - Parent issue (if any) as a team_number code                                      
+  --due-date          <dueDate>      - Due date of the issue. Use --clear-due-date to remove it                         
+  --clear-due-date                   - Remove the issue's due date (cannot be combined with --due-date)                 
+  --parent            <parent>       - Parent issue (if any) as a team_number code. Use --clear-parent to remove it     
+  --clear-parent                     - Remove the issue's parent (cannot be combined with --parent)                     
   -p, --priority      <priority>     - Priority of the issue (1-4, descending priority)                                 
-  --estimate          <estimate>     - Points estimate of the issue                                                     
+  --estimate          <estimate>     - Points estimate of the issue. Use --clear-estimate to remove it                  
+  --clear-estimate                   - Remove the issue's estimate (cannot be combined with --estimate)                 
   -d, --description   <description>  - Description of the issue                                                         
   --description-file  <path>         - Read description from a file (preferred for markdown content)                    
   -l, --label         <label>        - Issue label associated with the issue; replaces the issue's entire label set.    
@@ -31,10 +34,15 @@ Options:
   --remove-label      <label>        - Remove a label from the issue, keeping its other labels (does not delete the     
                                        label from the team). May be repeated.                                           
   --team              <team>         - Team (key, name, or ID) to move the issue to                                     
-  --project           <project>      - Project to assign the issue to (UUID, slug ID, or name)                          
+  --project           <project>      - Project to assign the issue to (UUID, slug ID, or name). Use --clear-project to  
+                                       remove it                                                                        
+  --clear-project                    - Remove the issue from its project (cannot be combined with --project or          
+                                       --milestone)                                                                     
   -s, --state         <state>        - Workflow state for the issue (by name or type)                                   
   --milestone         <milestone>    - Project milestone (UUID, or name when --project is set or the issue already has  
-                                       a project)                                                                       
+                                       a project). Use --clear-milestone to remove it                                   
+  --clear-milestone                  - Remove the issue from its project milestone (cannot be combined with             
+                                       --milestone)                                                                     
   --cycle             <cycle>        - Cycle name, number, 'active'/'now', 'next', 'previous', or a relative offset     
                                        like +1 (use --cycle=-1 for negatives). Use --clear-cycle to remove the issue    
                                        from its cycle                                                                   
@@ -357,3 +365,25 @@ https://linear.app/test-team/issue/APP-7/moved
 stderr:
 ""
 `;
+
+snapshot[`Issue Update Command - Clear Flags Send Null 1`] = `
+stdout:
+"Updating issue ENG-123
+
+✓ Updated issue ENG-123: Some issue
+https://linear.app/test-team/issue/ENG-123/some-issue
+"
+stderr:
+""
+`;
+
+snapshot[`Issue Update Command - Project With Clear Milestone 1`] = `
+stdout:
+"Updating issue ENG-123
+
+✓ Updated issue ENG-123: Some issue
+https://linear.app/test-team/issue/ENG-123/some-issue
+"
+stderr:
+""
+`;
diff --git a/test/commands/issue/issue-update.test.ts b/test/commands/issue/issue-update.test.ts
index 861278d5..da4b4cfd 100644
--- a/test/commands/issue/issue-update.test.ts
+++ b/test/commands/issue/issue-update.test.ts
@@ -1946,3 +1946,190 @@ await snapshotTest({
     }
   },
 })
+
+// Every clear flag must send its field as an explicit null. As with
+// --unassign and --clear-cycle above, the exact-variables mock proves each key
+// is present AND null. There are no GetProjectIdByName, GetIssueProjectId,
+// GetProjectMilestonesForLookup, or GetIssueId mocks: clearing must not
+// resolve anything.
+await snapshotTest({
+  name: "Issue Update Command - Clear Flags Send Null",
+  meta: import.meta,
+  colors: false,
+  args: [
+    "ENG-123",
+    "--clear-due-date",
+    "--clear-estimate",
+    "--clear-parent",
+    "--clear-project",
+    "--clear-milestone",
+  ],
+  denoArgs: commonDenoArgs,
+  async fn() {
+    const { cleanup } = await setupMockLinearServer([
+      resolveTeamMock("ENG"),
+      {
+        queryName: "UpdateIssue",
+        variables: {
+          id: "ENG-123",
+          input: {
+            dueDate: null,
+            parentId: null,
+            estimate: null,
+            teamId: "team-eng-id",
+            projectId: null,
+            projectMilestoneId: null,
+          },
+        },
+        response: {
+          data: {
+            issueUpdate: {
+              success: true,
+              issue: {
+                id: "issue-existing-123",
+                identifier: "ENG-123",
+                url: "https://linear.app/test-team/issue/ENG-123/some-issue",
+                title: "Some issue",
+              },
+            },
+          },
+        },
+      },
+    ], { LINEAR_TEAM_ID: "ENG" })
+
+    try {
+      await updateCommand.parse()
+    } finally {
+      await cleanup()
+    }
+  },
+})
+
+// Moving an issue to a project while detaching its milestone: the project is
+// resolved, the milestone is nulled, and neither GetIssueProjectId nor a
+// milestone lookup runs (no mocks for them).
+await snapshotTest({
+  name: "Issue Update Command - Project With Clear Milestone",
+  meta: import.meta,
+  colors: false,
+  args: ["ENG-123", "--project", "Mobile App", "--clear-milestone"],
+  denoArgs: commonDenoArgs,
+  async fn() {
+    const { cleanup } = await setupMockLinearServer([
+      resolveTeamMock("ENG"),
+      {
+        queryName: "GetProjectIdByName",
+        variables: { name: "Mobile App" },
+        response: {
+          data: { projects: { nodes: [{ id: "project-mobile" }] } },
+        },
+      },
+      {
+        queryName: "UpdateIssue",
+        variables: {
+          id: "ENG-123",
+          input: {
+            teamId: "team-eng-id",
+            projectId: "project-mobile",
+            projectMilestoneId: null,
+          },
+        },
+        response: {
+          data: {
+            issueUpdate: {
+              success: true,
+              issue: {
+                id: "issue-existing-123",
+                identifier: "ENG-123",
+                url: "https://linear.app/test-team/issue/ENG-123/some-issue",
+                title: "Some issue",
+              },
+            },
+          },
+        },
+      },
+    ], { LINEAR_TEAM_ID: "ENG" })
+
+    try {
+      await updateCommand.parse()
+    } finally {
+      await cleanup()
+    }
+  },
+})
+
+// Each clear flag conflicts with its set flag. The endpoint is dead, so these
+// only pass if the command errors before any request. `--estimate 0` guards
+// the null check: zero is an explicit value, not an omission.
+Deno.test("Issue Update Command - clear flags reject their set flags", async (t) => {
+  const { assertEquals } = await import("@std/assert")
+  const { stub } = await import("@std/testing/mock")
+  const cases: { args: string[]; message: string; suggestion: string }[] = [
+    {
+      args: ["--due-date", "2026-10-01", "--clear-due-date"],
+      message: "Cannot specify both --due-date and --clear-due-date",
+      suggestion: "--clear-due-date on its own",
+    },
+    {
+      args: ["--estimate", "0", "--clear-estimate"],
+      message: "Cannot specify both --estimate and --clear-estimate",
+      suggestion: "--clear-estimate on its own",
+    },
+    {
+      args: ["--parent", "ENG-1", "--clear-parent"],
+      message: "Cannot specify both --parent and --clear-parent",
+      suggestion: "--clear-parent on its own",
+    },
+    {
+      args: ["--project", "Mobile App", "--clear-project"],
+      message: "Cannot specify both --project and --clear-project",
+      suggestion: "--clear-project on its own",
+    },
+    {
+      args: ["--milestone", "Phase 2", "--clear-milestone"],
+      message: "Cannot specify both --milestone and --clear-milestone",
+      suggestion: "--clear-milestone on its own",
+    },
+    {
+      args: [
+        "--clear-project",
+        "--milestone",
+        "0d7a1d1e-4b1e-4d7e-9c5e-1f0f8a2b3c4d",
+      ],
+      message: "Cannot specify --milestone while clearing the issue's project",
+      suggestion: "replace it with --clear-milestone",
+    },
+  ]
+
+  Deno.env.set("LINEAR_GRAPHQL_ENDPOINT", "http://127.0.0.1:1")
+  Deno.env.set("LINEAR_API_KEY", "Bearer test-token")
+  try {
+    for (const c of cases) {
+      await t.step(c.args.join(" "), async () => {
+        const errorLogs: string[] = []
+        const errorStub = stub(console, "error", (...args: unknown[]) => {
+          errorLogs.push(args.map(String).join(" "))
+        })
+        const exitStub = stub(Deno, "exit", (_code?: number) => {
+          throw new Error("EXIT")
+        })
+        let exited = false
+        try {
+          await updateCommand.parse(["ENG-123", ...c.args])
+        } catch (e) {
+          if (!(e instanceof Error) || e.message !== "EXIT") throw e
+          exited = true
+        } finally {
+          errorStub.restore()
+          exitStub.restore()
+        }
+        assertEquals(exited, true)
+        assertEquals(errorLogs.some((l) => l.includes(c.message)), true)
+        assertEquals(errorLogs.some((l) => l.includes(c.suggestion)), true)
+      })
+    }
+  } finally {
+    Deno.env.delete("LINEAR_GRAPHQL_ENDPOINT")
+    Deno.env.delete("LINEAR_API_KEY")
+  }
+})
diff --git a/test/commands/project/__snapshots__/project-update.test.ts.snap b/test/commands/project/__snapshots__/project-update.test.ts.snap
index e9daa810..7080a982 100644
--- a/test/commands/project/__snapshots__/project-update.test.ts.snap
+++ b/test/commands/project/__snapshots__/project-update.test.ts.snap
@@ -24,9 +24,12 @@ Options:
   --content               <markdown>     - Project overview markdown                                                   
   --content-file          <path>         - Read project overview markdown from a file                                  
   -s, --status            <status>       - Status (planned, started, paused, completed, canceled, backlog)             
-  -l, --lead              <lead>         - Project lead (username, email, or @me)                                      
-  --start-date            <startDate>    - Start date (YYYY-MM-DD)                                                     
-  --target-date           <targetDate>   - Target date (YYYY-MM-DD)                                                    
+  -l, --lead              <lead>         - Project lead (username, email, or @me). Use --clear-lead to remove it       
+  --clear-lead                           - Remove the project's lead (cannot be combined with --lead)                  
+  --start-date            <startDate>    - Start date (YYYY-MM-DD). Use --clear-start-date to remove it                
+  --clear-start-date                     - Remove the project's start date (cannot be combined with --start-date)      
+  --target-date           <targetDate>   - Target date (YYYY-MM-DD). Use --clear-target-date to remove it              
+  --clear-target-date                    - Remove the project's target date (cannot be combined with --target-date)    
   -t, --team              <team>         - Team key, name, or ID (can be repeated for multiple teams)                  
   --label                 <label>        - Replace the project's labels. May be repeated to set multiple labels.       
 
diff --git a/test/commands/project/project-update.test.ts b/test/commands/project/project-update.test.ts
index 4401c7a6..70edd22b 100644
--- a/test/commands/project/project-update.test.ts
+++ b/test/commands/project/project-update.test.ts
@@ -508,6 +508,11 @@ Deno.test("Project Update Command - requires at least one option", async () => {
     ),
     true,
   )
+  for (
+    const flag of ["--clear-lead", "--clear-start-date", "--clear-target-date"]
+  ) {
+    assertEquals(errorLogs.some((l) => l.includes(flag)), true, flag)
+  }
 })
 
 // --- content (the long-form overview body) ---------------------------------
@@ -736,3 +741,94 @@ Deno.test("Project Update Command - errors on a missing content file", async ()
     true,
   )
 })
+
+// Each clear flag on its own is a valid update (it passes the at-least-one
+// option guard) and sends its field as an explicit null. The exact-variables
+// mock proves the key is present AND null and that nothing else is sent. There
+// is no GetViewerId/user lookup mock: --clear-lead must not resolve a user.
+Deno.test("Project Update Command - clear flags send null", async (t) => {
+  const cases: { flag: string; input: Record<string, null> }[] = [
+    { flag: "--clear-lead", input: { leadId: null } },
+    { flag: "--clear-start-date", input: { startDate: null } },
+    { flag: "--clear-target-date", input: { targetDate: null } },
+  ]
+  for (const c of cases) {
+    await t.step(c.flag, async () => {
+      const server = new MockLinearServer([
+        {
+          queryName: "UpdateProject",
+          variables: {
+            id: "550e8400-e29b-41d4-a716-446655440009",
+            input: c.input,
+          },
+          response: {
+            data: {
+              projectUpdate: {
+                success: true,
+                project: {
+                  id: "550e8400-e29b-41d4-a716-446655440009",
+                  slugId: "proj-clear",
+                  name: "Test Project",
+                  description: null,
+                  url: "https://linear.app/test/project/proj-clear",
+                  updatedAt: "2024-01-20T15:30:00Z",
+                },
+              },
+            },
+          },
+        },
+      ])
+      const logs: string[] = []
+      const logStub = stub(console, "log", (...args: unknown[]) => {
+        logs.push(args.map(String).join(" "))
+      })
+      try {
+        await server.start()
+        Deno.env.set("LINEAR_GRAPHQL_ENDPOINT", server.getEndpoint())
+        Deno.env.set("LINEAR_API_KEY", "Bearer test-token")
+        await updateCommand.parse([
+          "550e8400-e29b-41d4-a716-446655440009",
+          c.flag,
+        ])
+      } finally {
+        logStub.restore()
+        await server.stop()
+        Deno.env.delete("LINEAR_GRAPHQL_ENDPOINT")
+        Deno.env.delete("LINEAR_API_KEY")
+      }
+      assertEquals(logs.some((l) => l.includes("✓ Updated project")), true)
+    })
+  }
+})
+
+// Each clear flag conflicts with its set flag. No server is configured, so
+// these only pass if the command errors before making any request.
+Deno.test("Project Update Command - clear flags reject their set flags", async (t) => {
+  const cases: { args: string[]; message: string; suggestion: string }[] = [
+    {
+      args: ["--lead", "jane", "--clear-lead"],
+      message: "Cannot specify both --lead and --clear-lead",
+      suggestion: "--clear-lead on its own",
+    },
+    {
+      args: ["--start-date", "2026-09-10", "--clear-start-date"],
+      message: "Cannot specify both --start-date and --clear-start-date",
+      suggestion: "--clear-start-date on its own",
+    },
+    {
+      args: ["--target-date", "2026-10-10", "--clear-target-date"],
+      message: "Cannot specify both --target-date and --clear-target-date",
+      suggestion: "--clear-target-date on its own",
+    },
+  ]
+  for (const c of cases) {
+    await t.step(c.args.join(" "), async () => {
+      const errorLogs = await expectUpdateToFail([
+        "550e8400-e29b-41d4-a716-446655440009",
+        ...c.args,
+      ])
+      assertEquals(errorLogs.some((l) => l.includes(c.message)), true)
+      assertEquals(errorLogs.some((l) => l.includes(c.suggestion)), true)
+    })
+  }
+})