diff --git a/src/apps/work/src/lib/components/ProjectRouteAccessGuard/ProjectRouteAccessGuard.spec.tsx b/src/apps/work/src/lib/components/ProjectRouteAccessGuard/ProjectRouteAccessGuard.spec.tsx
new file mode 100644
index 000000000..15862142d
--- /dev/null
+++ b/src/apps/work/src/lib/components/ProjectRouteAccessGuard/ProjectRouteAccessGuard.spec.tsx
@@ -0,0 +1,219 @@
+/* eslint-disable no-var, global-require, @typescript-eslint/no-var-requires */
+/* eslint-disable import/no-extraneous-dependencies, ordered-imports/ordered-imports */
+import type {
+    Context,
+    PropsWithChildren,
+} from 'react'
+import {
+    render,
+    screen,
+} from '@testing-library/react'
+import {
+    MemoryRouter,
+    Route,
+    Routes,
+} from 'react-router-dom'
+
+import { WorkAppContextModel } from '../../models'
+import { useFetchProject } from '../../hooks'
+import { checkProjectAccess } from '../../utils'
+
+import {
+    PROJECT_ACCESS_DENIED_MESSAGE,
+    ProjectRouteAccessGuard,
+} from './ProjectRouteAccessGuard'
+
+var mockWorkAppContext: Context<WorkAppContextModel>
+
+jest.mock('~/apps/review/src/lib', () => ({
+    PageWrapper: (
+        props: PropsWithChildren<{
+            pageTitle?: string
+        }>,
+    ) => (
+        <div>
+            <h1>{props.pageTitle}</h1>
+            <div data-testid='page-content'>{props.children}</div>
+        </div>
+    ),
+}), {
+    virtual: true,
+})
+jest.mock('~/libs/ui', () => ({
+    Button: (props: { label: string }) => (
+        <button type='button'>{props.label}</button>
+    ),
+    LoadingSpinner: () => <div>Loading Spinner</div>,
+}), {
+    virtual: true,
+})
+jest.mock('../../contexts', () => {
+    const React = require('react') as typeof import('react')
+
+    mockWorkAppContext = React.createContext<WorkAppContextModel>({
+        isAdmin: false,
+        isAnonymous: false,
+        isCopilot: false,
+        isManager: false,
+        isReadOnly: false,
+        loginUserInfo: undefined,
+        userRoles: [],
+    })
+
+    return {
+        WorkAppContext: mockWorkAppContext,
+    }
+})
+jest.mock('../../hooks', () => ({
+    useFetchProject: jest.fn(),
+}))
+jest.mock('../../utils', () => ({
+    checkProjectAccess: jest.fn(),
+}))
+
+const mockedUseFetchProject = useFetchProject as jest.Mock
+const mockedCheckProjectAccess = checkProjectAccess as jest.Mock
+
+const defaultContextValue: WorkAppContextModel = {
+    isAdmin: false,
+    isAnonymous: false,
+    isCopilot: false,
+    isManager: true,
+    isReadOnly: false,
+    loginUserInfo: {
+        email: 'manager@example.com',
+        exp: 0,
+        handle: 'manager-user',
+        iat: 0,
+        roles: ['Project Manager'],
+        userId: 12345,
+    } as WorkAppContextModel['loginUserInfo'],
+    userRoles: ['Project Manager'],
+}
+
+function renderGuard(
+    route: string,
+    contextValue: WorkAppContextModel = defaultContextValue,
+): void {
+    const MockWorkAppContext = mockWorkAppContext
+
+    render(
+        <MockWorkAppContext.Provider value={contextValue}>
+            <MemoryRouter initialEntries={[route]}>
+                <Routes>
+                    <Route
+                        path='/projects/:projectId/users'
+                        element={(
+                            <ProjectRouteAccessGuard pageTitle='Users'>
+                                <div>Protected Project Users</div>
+                            </ProjectRouteAccessGuard>
+                        )}
+                    />
+                </Routes>
+            </MemoryRouter>
+        </MockWorkAppContext.Provider>,
+    )
+}
+
+describe('ProjectRouteAccessGuard', () => {
+    beforeEach(() => {
+        jest.clearAllMocks()
+        mockedUseFetchProject.mockReturnValue({
+            error: undefined,
+            isLoading: false,
+            mutate: jest.fn(),
+            project: {
+                id: 200,
+                members: [{
+                    userId: 12345,
+                }],
+            },
+        })
+        mockedCheckProjectAccess.mockReturnValue(true)
+    })
+
+    it('renders the protected route when project access is allowed', () => {
+        renderGuard('/projects/200/users')
+
+        expect(mockedCheckProjectAccess)
+            .toHaveBeenCalledWith(defaultContextValue.userRoles, 12345, expect.objectContaining({ id: 200 }))
+        expect(screen.getByText('Protected Project Users'))
+            .toBeTruthy()
+    })
+
+    it('renders the protected route when cached project access survives a revalidation error', () => {
+        mockedUseFetchProject.mockReturnValue({
+            error: new Error('Network unavailable'),
+            isLoading: false,
+            mutate: jest.fn(),
+            project: {
+                id: 200,
+                members: [{
+                    userId: 12345,
+                }],
+            },
+        })
+        mockedCheckProjectAccess.mockReturnValue(true)
+
+        renderGuard('/projects/200/users')
+
+        expect(mockedCheckProjectAccess)
+            .toHaveBeenCalledWith(defaultContextValue.userRoles, 12345, expect.objectContaining({ id: 200 }))
+        expect(screen.getByText('Protected Project Users'))
+            .toBeTruthy()
+        expect(screen.queryByText(PROJECT_ACCESS_DENIED_MESSAGE))
+            .toBeNull()
+    })
+
+    it('shows loading while project access is resolving', () => {
+        mockedUseFetchProject.mockReturnValue({
+            error: undefined,
+            isLoading: true,
+            mutate: jest.fn(),
+            project: undefined,
+        })
+
+        renderGuard('/projects/200/users')
+
+        expect(screen.getByRole('heading', { level: 1, name: 'Users' }))
+            .toBeTruthy()
+        expect(screen.getByText('Loading Spinner'))
+            .toBeTruthy()
+        expect(screen.queryByText('Protected Project Users'))
+            .toBeNull()
+        expect(mockedCheckProjectAccess)
+            .not.toHaveBeenCalled()
+    })
+
+    it('shows the project access denial message when project access is rejected', () => {
+        mockedCheckProjectAccess.mockReturnValue(false)
+
+        renderGuard('/projects/200/users')
+
+        expect(screen.getByRole('heading', { level: 1, name: 'Users' }))
+            .toBeTruthy()
+        expect(screen.getByText(PROJECT_ACCESS_DENIED_MESSAGE))
+            .toBeTruthy()
+        expect(screen.queryByText('Protected Project Users'))
+            .toBeNull()
+    })
+
+    it('shows the project access denial message when the project fetch fails', () => {
+        mockedUseFetchProject.mockReturnValue({
+            error: new Error('Forbidden'),
+            isLoading: false,
+            mutate: jest.fn(),
+            project: undefined,
+        })
+        mockedCheckProjectAccess.mockReturnValue(false)
+
+        renderGuard('/projects/200/users')
+
+        expect(mockedCheckProjectAccess)
+            .toHaveBeenCalledWith(defaultContextValue.userRoles, 12345, undefined)
+        expect(screen.getByText(PROJECT_ACCESS_DENIED_MESSAGE))
+            .toBeTruthy()
+        expect(screen.queryByText('Protected Project Users'))
+            .toBeNull()
+    })
+})
diff --git a/src/apps/work/src/lib/components/ProjectRouteAccessGuard/ProjectRouteAccessGuard.tsx b/src/apps/work/src/lib/components/ProjectRouteAccessGuard/ProjectRouteAccessGuard.tsx
new file mode 100644
index 000000000..21dc756f4
--- /dev/null
+++ b/src/apps/work/src/lib/components/ProjectRouteAccessGuard/ProjectRouteAccessGuard.tsx
@@ -0,0 +1,77 @@
+import {
+    FC,
+    PropsWithChildren,
+    useContext,
+} from 'react'
+import { useParams } from 'react-router-dom'
+
+import { PageWrapper } from '~/apps/review/src/lib'
+
+import { WorkAppContext } from '../../contexts'
+import { useFetchProject } from '../../hooks'
+import { WorkAppContextModel } from '../../models'
+import { checkProjectAccess } from '../../utils'
+import { ErrorMessage } from '../ErrorMessage'
+import { LoadingSpinner } from '../LoadingSpinner'
+
+export const PROJECT_ACCESS_DENIED_MESSAGE
+    = 'You don’t have access to this project. Please contact support@topcoder.com.'
+
+interface ProjectRouteAccessGuardProps extends PropsWithChildren {
+    pageTitle: string
+}
+
+/**
+ * Blocks project-scoped Work routes until the current user has project access.
+ *
+ * @param props child route content and fallback page title used while access is loading or denied.
+ * @returns child route content when the project exists and the caller is an admin or project member.
+ * @remarks Used by project workspace routes so unauthorized users do not mount pages that fetch project child data.
+ * Access decisions use cached project data when available, so SWR revalidation errors do not block authorized users.
+ * @throws Does not throw; missing project access renders the standard project access denial message.
+ */
+export const ProjectRouteAccessGuard: FC<ProjectRouteAccessGuardProps> = (
+    props: ProjectRouteAccessGuardProps,
+) => {
+    const params: Readonly<{ projectId?: string }> = useParams<'projectId'>()
+    const projectId = params.projectId?.trim()
+
+    const workAppContext = useContext(WorkAppContext) as WorkAppContextModel
+    const projectResult = useFetchProject(projectId || undefined)
+
+    if (!projectId) {
+        return <>{props.children}</>
+    }
+
+    if (projectResult.isLoading) {
+        return (
+            <PageWrapper
+                breadCrumb={[]}
+                pageTitle={props.pageTitle}
+            >
+                <LoadingSpinner />
+            </PageWrapper>
+        )
+    }
+
+    const hasProjectAccess = checkProjectAccess(
+        workAppContext.userRoles,
+        workAppContext.loginUserInfo?.userId,
+        projectResult.project,
+    )
+
+    if (!hasProjectAccess) {
+        return (
+            <PageWrapper
+                breadCrumb={[]}
+                pageTitle={props.pageTitle}
+            >
+                <ErrorMessage message={PROJECT_ACCESS_DENIED_MESSAGE} />
+            </PageWrapper>
+        )
+    }
+
+    return <>{props.children}</>
+}
+
+export default ProjectRouteAccessGuard
diff --git a/src/apps/work/src/lib/components/ProjectRouteAccessGuard/index.ts b/src/apps/work/src/lib/components/ProjectRouteAccessGuard/index.ts
new file mode 100644
index 000000000..c9831bfb9
--- /dev/null
+++ b/src/apps/work/src/lib/components/ProjectRouteAccessGuard/index.ts
@@ -0,0 +1 @@
+export * from './ProjectRouteAccessGuard'
diff --git a/src/apps/work/src/lib/components/index.ts b/src/apps/work/src/lib/components/index.ts
index ee606c570..29122df08 100644
--- a/src/apps/work/src/lib/components/index.ts
+++ b/src/apps/work/src/lib/components/index.ts
@@ -22,6 +22,7 @@ export * from './Pagination'
 export * from './ProjectCard'
 export * from './ProjectBillingAccountExpiredNotice'
 export * from './ProjectListTabs'
+export * from './ProjectRouteAccessGuard'
 export * from './ProjectStatus'
 export * from './PaymentFormModal'
 export * from './PaymentHistoryModal'
diff --git a/src/apps/work/src/work-app.routes.tsx b/src/apps/work/src/work-app.routes.tsx
index 68758d959..250452f52 100644
--- a/src/apps/work/src/work-app.routes.tsx
+++ b/src/apps/work/src/work-app.routes.tsx
@@ -39,7 +39,10 @@ import {
     usersRouteId,
 } from './config/routes.config'
 import { WORK_MANAGER_ALLOWED_ROLES } from './config/access.config'
-import { ErrorMessage } from './lib/components'
+import {
+    ErrorMessage,
+    ProjectRouteAccessGuard,
+} from './lib/components'
 import { WorkAppContext } from './lib/contexts'
 import { WorkAppContextModel } from './lib/models'
 import { canViewAllEngagements } from './lib/utils'
@@ -222,7 +225,11 @@ export const workRoutes: ReadonlyArray<PlatformRoute> = [
             },
             {
                 authRequired: true,
-                element: <ProjectAssetsPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Project Assets'>
+                        <ProjectAssetsPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: projectAssetsRouteId,
                 route: '/projects/:projectId/assets',
                 title: 'Project Assets',
@@ -261,48 +268,76 @@ export const workRoutes: ReadonlyArray<PlatformRoute> = [
             },
             {
                 authRequired: true,
-                element: <EngagementsListPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Engagements'>
+                        <EngagementsListPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 route: '/projects/:projectId/engagements',
                 title: 'Engagements',
             },
             {
                 authRequired: true,
-                element: <EngagementEditorPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Create Engagement'>
+                        <EngagementEditorPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: engagementCreateRouteId,
                 route: '/projects/:projectId/engagements/new',
                 title: 'Create Engagement',
             },
             {
                 authRequired: true,
-                element: <EngagementEditorPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Edit Engagement'>
+                        <EngagementEditorPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: engagementEditRouteId,
                 route: '/projects/:projectId/engagements/:engagementId',
                 title: 'Edit Engagement',
             },
             {
                 authRequired: true,
-                element: <ApplicationsListPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Applications'>
+                        <ApplicationsListPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: engagementApplicationsRouteId,
                 route: '/projects/:projectId/engagements/:engagementId/applications',
                 title: 'Applications',
             },
             {
                 authRequired: true,
-                element: <EngagementPaymentPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Assignments'>
+                        <EngagementPaymentPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: engagementAssignmentsRouteId,
                 route: '/projects/:projectId/engagements/:engagementId/assignments',
                 title: 'Assignments',
             },
             {
                 authRequired: true,
-                element: <EngagementFeedbackPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Feedback'>
+                        <EngagementFeedbackPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: engagementFeedbackRouteId,
                 route: '/projects/:projectId/engagements/:engagementId/assignments/:assignmentId/feedback',
                 title: 'Feedback',
             },
             {
                 authRequired: true,
-                element: <EngagementExperiencePage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Experience'>
+                        <EngagementExperiencePage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: engagementExperienceRouteId,
                 route: '/projects/:projectId/engagements/:engagementId/assignments/:assignmentId/experience',
                 title: 'Experience',
@@ -349,7 +384,11 @@ export const workRoutes: ReadonlyArray<PlatformRoute> = [
             },
             {
                 authRequired: true,
-                element: <UsersManagementPage />,
+                element: (
+                    <ProjectRouteAccessGuard pageTitle='Users'>
+                        <UsersManagementPage />
+                    </ProjectRouteAccessGuard>
+                ),
                 id: usersRouteId,
                 route: '/projects/:projectId/users',
                 title: 'Users',