diff --git a/packages/vitest/src/node/pool.ts b/packages/vitest/src/node/pool.ts
index 8f6a59fd8385..f48edac4f27e 100644
--- a/packages/vitest/src/node/pool.ts
+++ b/packages/vitest/src/node/pool.ts
@@ -89,6 +89,9 @@ export function createPool(ctx: Vitest): ProcessPool {
     const environments = await getSpecificationsEnvironments(specs)
     const groups = groupSpecs(sorted)
 
+    const projectEnvs = new WeakMap<TestProject, Partial<NodeJS.ProcessEnv>>()
+    const projectExecArgvs = new WeakMap<TestProject, string[]>()
+
     for (const group of groups) {
       if (!group) {
         continue
@@ -114,6 +117,33 @@ export function createPool(ctx: Vitest): ProcessPool {
           throw new Error(`Cannot find the environment. This is a bug in Vitest.`)
         }
 
+        let env = projectEnvs.get(project)
+        if (!env) {
+          env = {
+            ...process.env,
+            ...options.env,
+            ...ctx.config.env,
+            ...project.config.env,
+          }
+
+          // env are case-insensitive on Windows, but spawned processes don't support it
+          if (isWindows) {
+            for (const name in env) {
+              env[name.toUpperCase()] = env[name]
+            }
+          }
+          projectEnvs.set(project, env)
+        }
+
+        let execArgv = projectExecArgvs.get(project)
+        if (!execArgv) {
+          execArgv = [
+            ...options.execArgv,
+            ...project.config.execArgv,
+          ]
+          projectExecArgvs.set(project, execArgv)
+        }
+
         taskGroup.push({
           context: {
             pool,
@@ -126,8 +156,8 @@ export function createPool(ctx: Vitest): ProcessPool {
             workerId: workerId++,
           },
           project,
-          env: { ...options.env, ...project.config.env },
-          execArgv: [...options.execArgv, ...project.config.execArgv],
+          env,
+          execArgv,
           worker: pool,
           isolate: project.config.isolate,
           memoryLimit: getMemoryLimit(ctx.config, pool) ?? null,
@@ -250,18 +280,9 @@ function resolveOptions(ctx: Vitest) {
       NODE_ENV: process.env.NODE_ENV || 'test',
       VITEST_MODE: ctx.config.watch ? 'WATCH' : 'RUN',
       FORCE_TTY: isatty(1) ? 'true' : '',
-      ...process.env,
-      ...ctx.config.env,
     },
   }
 
-  // env are case-insensitive on Windows, but spawned processes don't support it
-  if (isWindows) {
-    for (const name in options.env) {
-      options.env[name.toUpperCase()] = options.env[name]
-    }
-  }
-
   return options
 }
 
diff --git a/packages/vitest/src/node/pools/types.ts b/packages/vitest/src/node/pools/types.ts
index ea805fc86c4f..c32269e393d1 100644
--- a/packages/vitest/src/node/pools/types.ts
+++ b/packages/vitest/src/node/pools/types.ts
@@ -41,7 +41,15 @@ export interface PoolTask {
   worker: 'forks' | 'threads' | 'vmForks' | 'vmThreads' | (string & {})
   project: TestProject
   isolate: boolean
+  /**
+   * Custom `process.env`. All tasks in the same project will reference the same object,
+   * so modifying it once will modify it for every task.
+   */
   env: Partial<NodeJS.ProcessEnv>
+  /**
+   * Custom `execArgv`. All tasks in the same project will reference the same array,
+   * so modifying it once will modify it for every task.
+   */
   execArgv: string[]
   context: ContextRPC
   memoryLimit: number | null
diff --git a/packages/vitest/src/node/pools/workers/vmForksWorker.ts b/packages/vitest/src/node/pools/workers/vmForksWorker.ts
index a2e5a6700abf..2cc5c8d2e870 100644
--- a/packages/vitest/src/node/pools/workers/vmForksWorker.ts
+++ b/packages/vitest/src/node/pools/workers/vmForksWorker.ts
@@ -9,8 +9,7 @@ export class VmForksPoolWorker extends ForksPoolWorker {
   protected readonly entrypoint: string
 
   constructor(options: PoolOptions) {
-    super(options)
-    this.execArgv.push('--experimental-vm-modules')
+    super({ ...options, execArgv: [...options.execArgv, '--experimental-vm-modules'] })
 
     /** Loads {@link file://./../../../runtime/workers/vmForks.ts} */
     this.entrypoint = resolve(options.distPath, 'workers/vmForks.js')
diff --git a/packages/vitest/src/node/pools/workers/vmThreadsWorker.ts b/packages/vitest/src/node/pools/workers/vmThreadsWorker.ts
index cf66dacae36d..779e45b3be67 100644
--- a/packages/vitest/src/node/pools/workers/vmThreadsWorker.ts
+++ b/packages/vitest/src/node/pools/workers/vmThreadsWorker.ts
@@ -9,8 +9,7 @@ export class VmThreadsPoolWorker extends ThreadsPoolWorker {
   protected readonly entrypoint: string
 
   constructor(options: PoolOptions) {
-    super(options)
-    this.execArgv.push('--experimental-vm-modules')
+    super({ ...options, execArgv: [...options.execArgv, '--experimental-vm-modules'] })
 
     /** Loads {@link file://./../../../runtime/workers/vmThreads.ts} */
     this.entrypoint = resolve(options.distPath, 'workers/vmThreads.js')
diff --git a/test/global-setup/globalSetup/update-env.ts b/test/global-setup/globalSetup/update-env.ts
new file mode 100644
index 000000000000..65a5483a7b9f
--- /dev/null
+++ b/test/global-setup/globalSetup/update-env.ts
@@ -0,0 +1,3 @@
+export default () => {
+  process.env.NEW_VALUE = 'true'
+}
diff --git a/test/global-setup/test/setup-files.test.ts b/test/global-setup/test/setup-files.test.ts
index 7c0f6b267cf0..6d0ccc2e526b 100644
--- a/test/global-setup/test/setup-files.test.ts
+++ b/test/global-setup/test/setup-files.test.ts
@@ -11,3 +11,7 @@ test('setup file has been loaded without relative path prefix', () => {
   const result = loaded
   expect(result).toBeTruthy()
 })
+
+test('the process.env is injected correctly', () => {
+  expect(process.env.NEW_VALUE).toBe('true')
+})
diff --git a/test/global-setup/vitest.config.ts b/test/global-setup/vitest.config.ts
index e330ce975bf8..cf17bb4e408d 100644
--- a/test/global-setup/vitest.config.ts
+++ b/test/global-setup/vitest.config.ts
@@ -20,6 +20,7 @@ export default defineConfig({
       './globalSetup/named-exports.js',
       './globalSetup/ts-with-imports.ts',
       './globalSetup/another-vite-instance.ts',
+      './globalSetup/update-env.ts',
     ],
   },
 })