diff --git a/backend/routes/sessions.js b/backend/routes/sessions.js
index 48a3608..9d31b36 100644
--- a/backend/routes/sessions.js
+++ b/backend/routes/sessions.js
@@ -315,6 +315,42 @@ router.delete('/:id/notes', authenticateToken, (req, res) => {
   }
 });
 
+// Archive a session (admin only)
+router.post('/:id/archive', authenticateToken, (req, res) => {
+  try {
+    const session = db.prepare('SELECT id, is_active FROM sessions WHERE id = ?').get(req.params.id);
+
+    if (!session) {
+      return res.status(404).json({ error: 'Session not found' });
+    }
+
+    if (session.is_active === 1) {
+      return res.status(400).json({ error: 'Cannot archive an active session. Please close it first.' });
+    }
+
+    db.prepare('UPDATE sessions SET archived = 1 WHERE id = ?').run(req.params.id);
+    res.json({ success: true });
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+// Unarchive a session (admin only)
+router.post('/:id/unarchive', authenticateToken, (req, res) => {
+  try {
+    const session = db.prepare('SELECT id FROM sessions WHERE id = ?').get(req.params.id);
+
+    if (!session) {
+      return res.status(404).json({ error: 'Session not found' });
+    }
+
+    db.prepare('UPDATE sessions SET archived = 0 WHERE id = ?').run(req.params.id);
+    res.json({ success: true });
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
 // Get games played in a session
 router.get('/:id/games', (req, res) => {
   try {
diff --git a/tests/api/session-archive.test.js b/tests/api/session-archive.test.js
index f1f205b..d6ae450 100644
--- a/tests/api/session-archive.test.js
+++ b/tests/api/session-archive.test.js
@@ -93,3 +93,81 @@ describe('GET /api/sessions — filter and limit', () => {
     expect(res.body).toHaveLength(8);
   });
 });
+
+describe('POST /api/sessions/:id/archive', () => {
+  beforeEach(() => {
+    cleanDb();
+  });
+
+  test('archives a closed session', async () => {
+    const session = seedSession({ is_active: 0, notes: null });
+
+    const res = await request(app)
+      .post(`/api/sessions/${session.id}/archive`)
+      .set('Authorization', getAuthHeader());
+
+    expect(res.status).toBe(200);
+    expect(res.body.success).toBe(true);
+
+    const check = await request(app).get(`/api/sessions/${session.id}`);
+    expect(check.body.archived).toBe(1);
+  });
+
+  test('returns 400 for active session', async () => {
+    const session = seedSession({ is_active: 1, notes: null });
+
+    const res = await request(app)
+      .post(`/api/sessions/${session.id}/archive`)
+      .set('Authorization', getAuthHeader());
+
+    expect(res.status).toBe(400);
+  });
+
+  test('returns 404 for non-existent session', async () => {
+    const res = await request(app)
+      .post('/api/sessions/9999/archive')
+      .set('Authorization', getAuthHeader());
+
+    expect(res.status).toBe(404);
+  });
+
+  test('returns 401 without auth', async () => {
+    const session = seedSession({ is_active: 0, notes: null });
+
+    const res = await request(app)
+      .post(`/api/sessions/${session.id}/archive`);
+
+    expect(res.status).toBe(401);
+  });
+});
+
+describe('POST /api/sessions/:id/unarchive', () => {
+  beforeEach(() => {
+    cleanDb();
+  });
+
+  test('unarchives an archived session', async () => {
+    const session = seedSession({ is_active: 0, notes: null });
+    require('../helpers/test-utils').db.prepare(
+      'UPDATE sessions SET archived = 1 WHERE id = ?'
+    ).run(session.id);
+
+    const res = await request(app)
+      .post(`/api/sessions/${session.id}/unarchive`)
+      .set('Authorization', getAuthHeader());
+
+    expect(res.status).toBe(200);
+    expect(res.body.success).toBe(true);
+
+    const check = await request(app).get(`/api/sessions/${session.id}`);
+    expect(check.body.archived).toBe(0);
+  });
+
+  test('returns 404 for non-existent session', async () => {
+    const res = await request(app)
+      .post('/api/sessions/9999/unarchive')
+      .set('Authorization', getAuthHeader());
+
+    expect(res.status).toBe(404);
+  });
+});