diff --git a/Dockerfile b/Dockerfile
index 8b39f2a..b652230 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 # Build stage
 # Matches the patch in go.mod. This tag is Alpine 3.24; the runtime stage stays on 3.21.
-FROM golang:1.26.10-alpine AS builder
+FROM golang:1.27.3-alpine AS builder
 
 WORKDIR /app
 
diff --git a/docs/CONTRIBUTE.md b/docs/CONTRIBUTE.md
index 59e16f0..299bfd8 100644
--- a/docs/CONTRIBUTE.md
+++ b/docs/CONTRIBUTE.md
@@ -34,7 +34,7 @@ We appreciate all kinds of contributions:
 
 ### 2. Set Up Your Environment
 
-- **Ensure you have a Go toolchain that matches `go.mod` (currently Go 1.26.x).**
+- **Ensure you have a Go toolchain that matches `go.mod` (currently Go 1.27.x).**
 - Install dependencies:
   ```bash
   make deps
diff --git a/go.mod b/go.mod
index 3064ab4..e307f67 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module inboundparse
 
-go 1.26.10
+go 1.27.3
 
 require (
 	github.com/emersion/go-msgauth v0.7.0