diff --git a/packages/cli/src/core/auth.test.ts b/packages/cli/src/core/auth.test.ts
index f28e826f49..5db9cd5449 100644
--- a/packages/cli/src/core/auth.test.ts
+++ b/packages/cli/src/core/auth.test.ts
@@ -9,6 +9,7 @@ import { performInitialAuth } from './auth.js';
 import {
   type Config,
   ValidationRequiredError,
+  ProjectIdRequiredError,
   AuthType,
 } from '@google/gemini-cli-core';
 
@@ -116,4 +117,22 @@ describe('auth', () => {
       AuthType.LOGIN_WITH_GOOGLE,
     );
   });
+
+  it('should return ProjectIdRequiredError message without "Failed to login" prefix', async () => {
+    const projectIdError = new ProjectIdRequiredError();
+    vi.mocked(mockConfig.refreshAuth).mockRejectedValue(projectIdError);
+    const result = await performInitialAuth(
+      mockConfig,
+      AuthType.LOGIN_WITH_GOOGLE,
+    );
+    expect(result).toEqual({
+      authError:
+        'This account requires setting the GOOGLE_CLOUD_PROJECT or GOOGLE_CLOUD_PROJECT_ID env var. See https://goo.gle/gemini-cli-auth-docs#workspace-gca',
+      accountSuspensionInfo: null,
+    });
+    expect(result.authError).not.toContain('Failed to login');
+    expect(mockConfig.refreshAuth).toHaveBeenCalledWith(
+      AuthType.LOGIN_WITH_GOOGLE,
+    );
+  });
 });
diff --git a/packages/cli/src/core/auth.ts b/packages/cli/src/core/auth.ts
index f49fdecf76..f0b8015013 100644
--- a/packages/cli/src/core/auth.ts
+++ b/packages/cli/src/core/auth.ts
@@ -10,6 +10,7 @@ import {
   getErrorMessage,
   ValidationRequiredError,
   isAccountSuspendedError,
+  ProjectIdRequiredError,
 } from '@google/gemini-cli-core';
 
 import type { AccountSuspensionInfo } from '../ui/contexts/UIStateContext.js';
@@ -54,6 +55,14 @@ export async function performInitialAuth(
         },
       };
     }
+    if (e instanceof ProjectIdRequiredError) {
+      // OAuth succeeded but account setup requires project ID
+      // Show the error message directly without "Failed to login" prefix
+      return {
+        authError: getErrorMessage(e),
+        accountSuspensionInfo: null,
+      };
+    }
     return {
       authError: `Failed to login. Message: ${getErrorMessage(e)}`,
       accountSuspensionInfo: null,
diff --git a/packages/cli/src/ui/AppContainer.tsx b/packages/cli/src/ui/AppContainer.tsx
index d656169c51..a51a12bf1d 100644
--- a/packages/cli/src/ui/AppContainer.tsx
+++ b/packages/cli/src/ui/AppContainer.tsx
@@ -80,6 +80,7 @@ import {
   type ConsentRequestPayload,
   type AgentsDiscoveredPayload,
   ChangeAuthRequestedError,
+  ProjectIdRequiredError,
   CoreToolCallStatus,
   generateSteeringAckMessage,
   buildUserSteeringHintPrompt,
@@ -771,6 +772,12 @@ export const AppContainer = (props: AppContainerProps) => {
           if (e instanceof ChangeAuthRequestedError) {
             return;
           }
+          if (e instanceof ProjectIdRequiredError) {
+            // OAuth succeeded but account setup requires project ID
+            // Show the error message directly without "Failed to authenticate" prefix
+            onAuthError(getErrorMessage(e));
+            return;
+          }
           onAuthError(
             `Failed to authenticate: ${e instanceof Error ? e.message : String(e)}`,
           );
diff --git a/packages/cli/src/ui/auth/useAuth.test.tsx b/packages/cli/src/ui/auth/useAuth.test.tsx
index 36d9aeec4f..20a02ffb21 100644
--- a/packages/cli/src/ui/auth/useAuth.test.tsx
+++ b/packages/cli/src/ui/auth/useAuth.test.tsx
@@ -15,7 +15,11 @@ import {
 } from 'vitest';
 import { renderHook } from '../../test-utils/render.js';
 import { useAuthCommand, validateAuthMethodWithSettings } from './useAuth.js';
-import { AuthType, type Config } from '@google/gemini-cli-core';
+import {
+  AuthType,
+  type Config,
+  ProjectIdRequiredError,
+} from '@google/gemini-cli-core';
 import { AuthState } from '../types.js';
 import type { LoadedSettings } from '../../config/settings.js';
 import { waitFor } from '../../test-utils/async.js';
@@ -288,5 +292,21 @@ describe('useAuth', () => {
         expect(result.current.authState).toBe(AuthState.Updating);
       });
     });
+
+    it('should handle ProjectIdRequiredError without "Failed to login" prefix', async () => {
+      const projectIdError = new ProjectIdRequiredError();
+      (mockConfig.refreshAuth as Mock).mockRejectedValue(projectIdError);
+      const { result } = renderHook(() =>
+        useAuthCommand(createSettings(AuthType.LOGIN_WITH_GOOGLE), mockConfig),
+      );
+
+      await waitFor(() => {
+        expect(result.current.authError).toBe(
+          'This account requires setting the GOOGLE_CLOUD_PROJECT or GOOGLE_CLOUD_PROJECT_ID env var. See https://goo.gle/gemini-cli-auth-docs#workspace-gca',
+        );
+        expect(result.current.authError).not.toContain('Failed to login');
+        expect(result.current.authState).toBe(AuthState.Updating);
+      });
+    });
   });
 });
diff --git a/packages/cli/src/ui/auth/useAuth.ts b/packages/cli/src/ui/auth/useAuth.ts
index 3faec2d5a8..afd438bb00 100644
--- a/packages/cli/src/ui/auth/useAuth.ts
+++ b/packages/cli/src/ui/auth/useAuth.ts
@@ -12,6 +12,7 @@ import {
   loadApiKey,
   debugLogger,
   isAccountSuspendedError,
+  ProjectIdRequiredError,
 } from '@google/gemini-cli-core';
 import { getErrorMessage } from '@google/gemini-cli-core';
 import { AuthState } from '../types.js';
@@ -143,6 +144,10 @@ export const useAuthCommand = (
             appealUrl: suspendedError.appealUrl,
             appealLinkText: suspendedError.appealLinkText,
           });
+        } else if (e instanceof ProjectIdRequiredError) {
+          // OAuth succeeded but account setup requires project ID
+          // Show the error message directly without "Failed to login" prefix
+          onAuthError(getErrorMessage(e));
         } else {
           onAuthError(`Failed to login. Message: ${getErrorMessage(e)}`);
         }