diff --git a/packages/vitest/src/node/cli/cli-api.ts b/packages/vitest/src/node/cli/cli-api.ts
index e6944c4d192c..60684870324d 100644
--- a/packages/vitest/src/node/cli/cli-api.ts
+++ b/packages/vitest/src/node/cli/cli-api.ts
@@ -5,7 +5,7 @@ import type { TestModule, TestSuite } from '../reporters/reported-tasks'
 import type { TestSpecification } from '../spec'
 import type { UserConfig, VitestEnvironment, VitestRunMode } from '../types/config'
 import { mkdirSync, writeFileSync } from 'node:fs'
-import { dirname, relative, resolve } from 'pathe'
+import { dirname, isAbsolute, relative, resolve } from 'pathe'
 import { CoverageProviderMap } from '../../utils/coverage'
 import { createVitest } from '../create'
 import { FilesNotFoundError, GitNotFoundError, IncludeTaskLocationDisabledError, LocationFilterFileNotFoundError, RangeLocationFilterProvidedError } from '../errors'
@@ -317,7 +317,7 @@ function getEnvPackageName(env: VitestEnvironment) {
   if (env in envPackageNames) {
     return (envPackageNames as any)[env]
   }
-  if (env[0] === '.' || env[0] === '/') {
+  if (env[0] === '.' || isAbsolute(env)) {
     return null
   }
   return `vitest-environment-${env}`
diff --git a/test/cli/test/run-custom-env.test.ts b/test/cli/test/run-custom-env.test.ts
index a252167159bc..382127c859de 100644
--- a/test/cli/test/run-custom-env.test.ts
+++ b/test/cli/test/run-custom-env.test.ts
@@ -1,3 +1,4 @@
+import { createRequire } from 'node:module'
 import { expect, test } from 'vitest'
 
 import { runVitest } from '../../test-utils'
@@ -17,3 +18,21 @@ test('correctly runs tests if custom env is a file', async () => {
   expect(stderr).toBe('')
   expect(exitCode).toBe(0)
 })
+
+test('correctly runs tests if custom env is an absolute path', async () => {
+  const require = createRequire(import.meta.url)
+
+  const { stderr, exitCode } = await runVitest({
+    root: './fixtures/custom-file-env',
+    config: false,
+    environment: require.resolve('vitest-environment-custom'),
+    environmentOptions: {
+      custom: {
+        option: 'custom-option',
+      },
+    },
+  })
+
+  expect(stderr).toBe('')
+  expect(exitCode).toBe(0)
+})