diff --git a/backend/open_webui/models/chats.py b/backend/open_webui/models/chats.py
index 0ac53a023..71e7b34bf 100644
--- a/backend/open_webui/models/chats.py
+++ b/backend/open_webui/models/chats.py
@@ -9,7 +9,7 @@ from open_webui.models.tags import TagModel, Tag, Tags
 from open_webui.env import SRC_LOG_LEVELS
 
 from pydantic import BaseModel, ConfigDict
-from sqlalchemy import BigInteger, Boolean, Column, String, Text, JSON
+from sqlalchemy import BigInteger, Boolean, Column, String, Text, JSON, Index
 from sqlalchemy import or_, func, select, and_, text
 from sqlalchemy.sql import exists
 
@@ -39,6 +39,20 @@ class Chat(Base):
     meta = Column(JSON, server_default="{}")
     folder_id = Column(Text, nullable=True)
 
+    __table_args__ = (
+        # Performance indexes for common queries
+        # WHERE folder_id = ...
+        Index('folder_id_idx', 'folder_id'),
+        # WHERE user_id = ... AND pinned = ...
+        Index('user_id_pinned_idx', 'user_id', 'pinned'),
+        # WHERE user_id = ... AND archived = ...
+        Index('user_id_archived_idx', 'user_id', 'archived'),
+        # WHERE user_id = ... ORDER BY updated_at DESC
+        Index('updated_at_user_id_idx', 'updated_at', 'user_id'),
+        # WHERE folder_id = ... AND user_id = ...
+        Index('folder_id_user_id_idx', 'folder_id', 'user_id'),
+    )
+
 
 class ChatModel(BaseModel):
     model_config = ConfigDict(from_attributes=True)
diff --git a/backend/open_webui/models/functions.py b/backend/open_webui/models/functions.py
index e98771fa0..af2311319 100644
--- a/backend/open_webui/models/functions.py
+++ b/backend/open_webui/models/functions.py
@@ -6,7 +6,7 @@ from open_webui.internal.db import Base, JSONField, get_db
 from open_webui.models.users import Users
 from open_webui.env import SRC_LOG_LEVELS
 from pydantic import BaseModel, ConfigDict
-from sqlalchemy import BigInteger, Boolean, Column, String, Text
+from sqlalchemy import BigInteger, Boolean, Column, String, Text, Index
 
 log = logging.getLogger(__name__)
 log.setLevel(SRC_LOG_LEVELS["MODELS"])
@@ -31,6 +31,10 @@ class Function(Base):
     updated_at = Column(BigInteger)
     created_at = Column(BigInteger)
 
+    __table_args__ = (
+        Index('is_global_idx', 'is_global'),
+    )
+
 
 class FunctionMeta(BaseModel):
     description: Optional[str] = None
diff --git a/backend/open_webui/models/tags.py b/backend/open_webui/models/tags.py
index 279dc624d..46e412d81 100644
--- a/backend/open_webui/models/tags.py
+++ b/backend/open_webui/models/tags.py
@@ -8,7 +8,7 @@ from open_webui.internal.db import Base, get_db
 
 from open_webui.env import SRC_LOG_LEVELS
 from pydantic import BaseModel, ConfigDict
-from sqlalchemy import BigInteger, Column, String, JSON, PrimaryKeyConstraint
+from sqlalchemy import BigInteger, Column, String, JSON, PrimaryKeyConstraint, Index
 
 log = logging.getLogger(__name__)
 log.setLevel(SRC_LOG_LEVELS["MODELS"])
@@ -24,8 +24,9 @@ class Tag(Base):
     user_id = Column(String)
     meta = Column(JSON, nullable=True)
 
-    # Unique constraint ensuring (id, user_id) is unique, not just the `id` column
-    __table_args__ = (PrimaryKeyConstraint("id", "user_id", name="pk_id_user_id"),)
+    __table_args__ = (
+        Index('user_id_idx', 'user_id'),
+    )
 
 
 class TagModel(BaseModel):