diff --git a/packages/artifact/__tests__/config.test.ts b/packages/artifact/__tests__/config.test.ts
index 3d14ace2b2..7d3be228e0 100644
--- a/packages/artifact/__tests__/config.test.ts
+++ b/packages/artifact/__tests__/config.test.ts
@@ -15,6 +15,11 @@ beforeEach(() => {
 })
 
 describe('isGhes', () => {
+  beforeEach(() => {
+    delete process.env.GITHUB_SERVER_URL
+    delete process.env.ACTIONS_RESULTS_URL
+  })
+
   it('should return false when the request domain is github.com', () => {
     process.env.GITHUB_SERVER_URL = 'https://github.com'
     expect(config.isGhes()).toBe(false)
@@ -35,10 +40,22 @@ describe('isGhes', () => {
     expect(config.isGhes()).toBe(false)
   })
 
-  it('should return false when the request domain is specific to an enterprise', () => {
+  it('should return true on a self-hosted enterprise hostname when ACTIONS_RESULTS_URL is unset', () => {
     process.env.GITHUB_SERVER_URL = 'https://my-enterprise.github.com'
     expect(config.isGhes()).toBe(true)
   })
+
+  it('should return false on a self-hosted enterprise hostname when ACTIONS_RESULTS_URL is set (v2 backend available)', () => {
+    process.env.GITHUB_SERVER_URL = 'https://my-enterprise.github.com'
+    process.env.ACTIONS_RESULTS_URL = 'https://results.example.com/'
+    expect(config.isGhes()).toBe(false)
+  })
+
+  it('should ignore ACTIONS_RESULTS_URL on github.com (already returns false there)', () => {
+    process.env.GITHUB_SERVER_URL = 'https://github.com'
+    process.env.ACTIONS_RESULTS_URL = 'https://results.example.com/'
+    expect(config.isGhes()).toBe(false)
+  })
 })
 
 describe('uploadChunkTimeoutEnv', () => {
diff --git a/packages/artifact/src/internal/shared/config.ts b/packages/artifact/src/internal/shared/config.ts
index 0a275fd5ee..2991f69f8e 100644
--- a/packages/artifact/src/internal/shared/config.ts
+++ b/packages/artifact/src/internal/shared/config.ts
@@ -34,7 +34,21 @@ export function isGhes(): boolean {
   const isGheHost = hostname.endsWith('.GHE.COM')
   const isLocalHost = hostname.endsWith('.LOCALHOST')
 
-  return !isGitHubHost && !isGheHost && !isLocalHost
+  const hostnameLooksLikeGhes =
+    !isGitHubHost && !isGheHost && !isLocalHost
+
+  // GHES 3.13+ ships the artifact-storage-v2 backend that the v4+
+  // artifact client requires. The runner exposes the backend's
+  // presence via ACTIONS_RESULTS_URL (which getResultsServiceUrl()
+  // already requires for upload/download/list to function). When
+  // that env var is set we know the backend is reachable, so an
+  // unrecognised hostname does not need to short-circuit into a
+  // GHESNotSupportedError.
+  if (hostnameLooksLikeGhes && process.env['ACTIONS_RESULTS_URL']) {
+    return false
+  }
+
+  return hostnameLooksLikeGhes
 }
 
 export function getGitHubWorkspaceDir(): string {