diff --git a/backend/open_webui/env.py b/backend/open_webui/env.py
index 02891d6810..b18ba46658 100644
--- a/backend/open_webui/env.py
+++ b/backend/open_webui/env.py
@@ -557,6 +557,12 @@ OAUTH_SESSION_TOKEN_ENCRYPTION_KEY = os.environ.get(
     "OAUTH_SESSION_TOKEN_ENCRYPTION_KEY", WEBUI_SECRET_KEY
 )
 
+# Maximum number of concurrent OAuth sessions per user per provider
+# This prevents unbounded session growth while allowing multi-device usage
+OAUTH_MAX_SESSIONS_PER_USER = int(
+    os.environ.get("OAUTH_MAX_SESSIONS_PER_USER", "10")
+)
+
 # Token Exchange Configuration
 # Allows external apps to exchange OAuth tokens for OpenWebUI tokens
 ENABLE_OAUTH_TOKEN_EXCHANGE = (
diff --git a/backend/open_webui/models/oauth_sessions.py b/backend/open_webui/models/oauth_sessions.py
index 538937483f..fbcd763f34 100644
--- a/backend/open_webui/models/oauth_sessions.py
+++ b/backend/open_webui/models/oauth_sessions.py
@@ -188,6 +188,7 @@ class OAuthSessionTable:
                 session = (
                     db.query(OAuthSession)
                     .filter_by(provider=provider, user_id=user_id)
+                    .order_by(OAuthSession.created_at.desc())
                     .first()
                 )
                 if session:
diff --git a/backend/open_webui/utils/oauth.py b/backend/open_webui/utils/oauth.py
index c849eb25a8..2cb552860c 100644
--- a/backend/open_webui/utils/oauth.py
+++ b/backend/open_webui/utils/oauth.py
@@ -69,6 +69,7 @@ from open_webui.env import (
     ENABLE_OAUTH_ID_TOKEN_COOKIE,
     ENABLE_OAUTH_EMAIL_FALLBACK,
     OAUTH_CLIENT_INFO_ENCRYPTION_KEY,
+    OAUTH_MAX_SESSIONS_PER_USER,
 )
 from open_webui.utils.misc import parse_duration
 from open_webui.utils.auth import get_password_hash, create_token
@@ -1679,11 +1680,23 @@ class OAuthManager:
             if "expires_in" in token and "expires_at" not in token:
                 token["expires_at"] = datetime.now().timestamp() + token["expires_in"]
 
-            # Clean up any existing sessions for this user/provider first
+            # Enforce max concurrent sessions per user/provider to prevent
+            # unbounded growth while allowing multi-device usage
             sessions = OAuthSessions.get_sessions_by_user_id(user.id, db=db)
-            for session in sessions:
-                if session.provider == provider:
-                    OAuthSessions.delete_session_by_id(session.id, db=db)
+            provider_sessions = sorted(
+                [
+                    for session in sessions
+                    if session.provider == provider
+                ],
+                key=lambda session: session.created_at,
+                reverse=True,
+            )
+            # Keep the newest sessions up to the limit, prune the rest
+            if len(provider_sessions) >= OAUTH_MAX_SESSIONS_PER_USER:
+                for old_session in provider_sessions[
+                    OAUTH_MAX_SESSIONS_PER_USER - 1 :
+                ]:
+                    OAuthSessions.delete_session_by_id(old_session.id, db=db)
 
             session = OAuthSessions.create_session(
                 user_id=user.id,