diff --git a/graphistry/client_session.py b/graphistry/client_session.py
index e1a3d9228a..82331eb9fa 100644
--- a/graphistry/client_session.py
+++ b/graphistry/client_session.py
@@ -71,6 +71,8 @@ def __init__(self) -> None:
 
         self.idp_name: Optional[str] = None
         self.sso_state: Optional[str] = None
+        self.sso_state_created_at: Optional[float] = None
+        self.sso_state_ttl_s: int = get_from_env("GRAPHISTRY_SSO_STATE_TTL_S", int, 300)
 
         self.personal_key: Optional[str] = None
         self.personal_key_id: Optional[str] = None
diff --git a/graphistry/exceptions.py b/graphistry/exceptions.py
index 6b059fad85..a5fecd3740 100644
--- a/graphistry/exceptions.py
+++ b/graphistry/exceptions.py
@@ -17,6 +17,13 @@ class SsoStateInvalidException(SsoException):
     """
     pass
 
+class SsoStateExpiredException(SsoException):
+    """
+    Raised when the SSO state has exceeded the client-side TTL,
+    meaning the server's PKCE verifier has likely expired.
+    """
+    pass
+
 
 
 class TokenExpireException(Exception):
diff --git a/graphistry/pygraphistry.py b/graphistry/pygraphistry.py
index fe460e74c3..bf63900cf0 100644
--- a/graphistry/pygraphistry.py
+++ b/graphistry/pygraphistry.py
@@ -19,7 +19,7 @@
 from . import bolt_util
 from .plotter import Plotter
 from .util import in_databricks, setup_logger, in_ipython
-from .exceptions import SsoRetrieveTokenTimeoutException, TokenExpireException, SsoStateInvalidException
+from .exceptions import SsoRetrieveTokenTimeoutException, TokenExpireException, SsoStateInvalidException, SsoStateExpiredException
 
 from .messages import (
     MSG_REGISTER_MISSING_PASSWORD,
@@ -315,6 +315,7 @@ def _handle_auth_url(self, auth_url: str, sso_timeout: Optional[int], sso_opt_in
                 self.session.org_name = org_name
                 # finish, set back to None
                 self.session.sso_state = None
+                self.session.sso_state_created_at = None
                 print("Successfully logged in")
                 self._maybe_switch_org(org_name)
                 return self.api_token()
@@ -334,6 +335,8 @@ def _handle_auth_url(self, auth_url: str, sso_timeout: Optional[int], sso_opt_in
             #     print("Keep trying to get token ...")
             #     time.sleep(5)
 
+            ttl_s = self.session.sso_state_ttl_s
+            print(f"SSO link expires in {ttl_s // 60} minutes. If you wait longer, re-run graphistry.register() for a fresh link.")
             print("Please run graphistry.sso_get_token() to complete the authentication")
             return None
 
@@ -352,6 +355,16 @@ def _sso_get_token(self) -> Tuple[Optional[str], Optional[str]]:
         if state is None:
             raise SsoStateInvalidException("[SSO] Invalid SSO state: NoneType encountered")
 
+        created_at = self.session.sso_state_created_at
+        ttl = self.session.sso_state_ttl_s
+        if created_at is not None and (time.time() - created_at) > ttl:
+            self.session.sso_state = None
+            self.session.sso_state_created_at = None
+            raise SsoStateExpiredException(
+                f"[SSO] SSO link expired (older than {ttl}s). "
+                f"Run graphistry.register(..., is_sso_login=True) to get a new link."
+            )
+
         # print("_sso_get_token : {}".format(state))
         arrow_uploader = ArrowUploader(
             client_session=self.session,
@@ -2494,6 +2507,7 @@ def sso_state(self, value: Optional[str] = None):
 
         # setter
         self.session.sso_state = value.strip()
+        self.session.sso_state_created_at = time.time()
 
     def scene_settings(self, 
         menu: Optional[bool] = None,
diff --git a/graphistry/tests/test_arrow_uploader.py b/graphistry/tests/test_arrow_uploader.py
index 9c8187bea6..caf1c57dea 100644
--- a/graphistry/tests/test_arrow_uploader.py
+++ b/graphistry/tests/test_arrow_uploader.py
@@ -489,3 +489,64 @@ def test_sso_get_token_missing_org_raises(self, mock_get):
 
         with pytest.raises(Exception):
             au.sso_get_token(state='ignored-valid')
+
+
+class TestSsoStateTtl(unittest.TestCase):
+
+    def setUp(self):
+        self.client = graphistry.PyGraphistry
+        self.client.session.sso_state = None
+        self.client.session.sso_state_created_at = None
+
+    def tearDown(self):
+        self.client.session.sso_state = None
+        self.client.session.sso_state_created_at = None
+
+    def test_sso_state_created_at_set_on_state_assignment(self):
+        import time
+        before = time.time()
+        self.client.sso_state('test-state-123')
+        after = time.time()
+        assert self.client.session.sso_state == 'test-state-123'
+        assert self.client.session.sso_state_created_at is not None
+        assert before <= self.client.session.sso_state_created_at <= after
+
+    def test_sso_state_ttl_default(self):
+        assert self.client.session.sso_state_ttl_s == 300
+
+    def test_expired_state_raises(self):
+        import time
+        from graphistry.exceptions import SsoStateExpiredException
+        self.client.sso_state('expired-state')
+        # Backdate created_at so it appears expired
+        self.client.session.sso_state_created_at = time.time() - 400
+        with pytest.raises(SsoStateExpiredException, match="expired"):
+            self.client._sso_get_token()
+        # State should be cleared
+        assert self.client.session.sso_state is None
+        assert self.client.session.sso_state_created_at is None
+
+    @mock.patch('requests.get')
+    def test_fresh_state_not_expired(self, mock_get):
+        import time
+        mock_resp = mock.Mock()
+        mock_resp.status_code = 200
+        mock_resp.raise_for_status = mock.Mock()
+        mock_resp.json.return_value = {
+            'status': 'OK',
+            'data': {
+                'token': 'tok123',
+                'active_organization': {
+                    'slug': 'test-org',
+                    'is_found': True,
+                    'is_member': True,
+                }
+            }
+        }
+        mock_get.return_value = mock_resp
+
+        self.client.sso_state('fresh-state')
+        # Just created, should not be expired
+        with mock.patch.object(type(self.client), '_maybe_switch_org'):
+            token, org_name = self.client._sso_get_token()
+        assert token is not None