diff --git a/packages/nuxt-cli/src/dev/pool.ts b/packages/nuxt-cli/src/dev/pool.ts
index de1df23a8..1e1660472 100644
--- a/packages/nuxt-cli/src/dev/pool.ts
+++ b/packages/nuxt-cli/src/dev/pool.ts
@@ -130,7 +130,7 @@ export class ForkPool {
       execArgv: ['--enable-source-maps'],
       stdio: pipeOutput ? ['ignore', 'pipe', 'pipe', 'ipc'] : undefined,
       env: {
-        ...process.env,
+        ...withoutDotenvVars(process.env),
         __NUXT__FORK: 'true',
         ...pipeOutput
           ? {
@@ -250,6 +250,19 @@ function trackServing(child: ChildProcess): Promise<void> {
   })
 }
 
+/**
+ * The environment without the variables `.env` files set in this process, so a
+ * fork reads them afresh. c12 only overwrites variables it set itself, and its
+ * record of those does not survive into a new process.
+ */
+function withoutDotenvVars(env: NodeJS.ProcessEnv): NodeJS.ProcessEnv {
+  const dotenvVars = (globalThis as { __c12_dotenv_vars__?: Map<object, Set<string>> }).__c12_dotenv_vars__?.get(env)
+  if (!dotenvVars?.size) {
+    return env
+  }
+  return Object.fromEntries(Object.entries(env).filter(([key]) => !dotenvVars.has(key)))
+}
+
 /** Colour settings for a piped fork, which cannot detect colour support itself. */
 function forcedColorEnv(): Record<string, string> {
   if (process.env.NO_COLOR || process.env.FORCE_COLOR) {