diff --git a/src/api/v1/auth.py b/src/api/v1/auth.py
index 48bfd26..1a0ff51 100644
--- a/src/api/v1/auth.py
+++ b/src/api/v1/auth.py
@@ -4,7 +4,7 @@ from datetime import datetime
 from fastapi import APIRouter, Depends, HTTPException, Header, Request, Query
 from bson import ObjectId
 
-from src.services.auth_service import AuthService
+from src.dependencies import AuthServiceDep
 from src.schemas.api_key import ApiKeyCreate, ApiKeyResponse, ApiKeyWithValueResponse, ApiKeyListResponse
 from src.schemas.team import TeamCreate
 from src.schemas.user import UserCreate
@@ -18,15 +18,13 @@ logger = logging.getLogger(__name__)
 
 router = APIRouter(tags=["Authentication"], prefix="/auth")
 
-# Initialize service
-auth_service = AuthService()
-
 @router.post("/api-keys", response_model=ApiKeyWithValueResponse, status_code=201)
 async def create_api_key(
     key_data: ApiKeyCreate, 
     request: Request, 
     user_id: str = Query(..., description="User ID for the API key"),
-    team_id: str = Query(..., description="Team ID for the API key")
+    team_id: str = Query(..., description="Team ID for the API key"),
+    auth_service: AuthServiceDep = Depends()
 ):
     """
     Create a new API key for a specific user and team
@@ -38,6 +36,7 @@ async def create_api_key(
         key_data: API key creation data including name and description
         user_id: The user ID to create the key for
         team_id: The team ID the user belongs to
+        auth_service: Injected authentication service
         
     Returns:
         ApiKeyWithValueResponse: The created API key with the raw key value
@@ -76,7 +75,8 @@ async def create_api_key_for_user(
     user_id: str,
     key_data: ApiKeyCreate,
     request: Request,
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    auth_service: AuthServiceDep = Depends()
 ):
     """
     Create a new API key for a specific user (admin only)
@@ -88,6 +88,7 @@ async def create_api_key_for_user(
         user_id: The target user ID to create the key for
         key_data: API key creation data including name and description
         current_user: The authenticated admin user
+        auth_service: Injected authentication service
         
     Returns:
         ApiKeyWithValueResponse: The created API key with the raw key value
@@ -129,7 +130,8 @@ async def create_api_key_for_user(
 @router.get("/api-keys", response_model=ApiKeyListResponse)
 async def list_api_keys(
     request: Request, 
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    auth_service: AuthServiceDep = Depends()
 ):
     """
     List API keys for the current authenticated user
@@ -138,6 +140,7 @@ async def list_api_keys(
     
     Args:
         current_user: The authenticated user
+        auth_service: Injected authentication service
         
     Returns:
         ApiKeyListResponse: List of API keys with metadata
@@ -163,7 +166,8 @@ async def list_api_keys(
 async def revoke_api_key(
     key_id: str, 
     request: Request, 
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    auth_service: AuthServiceDep = Depends()
 ):
     """
     Revoke (deactivate) an API key
@@ -173,6 +177,7 @@ async def revoke_api_key(
     Args:
         key_id: The ID of the API key to revoke
         current_user: The authenticated user
+        auth_service: Injected authentication service
         
     Returns:
         None (204 No Content)
@@ -209,7 +214,8 @@ async def revoke_api_key(
 @router.get("/verify", status_code=200)
 async def verify_authentication(
     request: Request, 
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    auth_service: AuthServiceDep = Depends()
 ):
     """
     Verify the current authentication status
@@ -219,6 +225,7 @@ async def verify_authentication(
     
     Args:
         current_user: The authenticated user
+        auth_service: Injected authentication service
         
     Returns:
         dict: Authentication verification response with user details
diff --git a/src/api/v1/images.py b/src/api/v1/images.py
index fec9911..7bbb8ab 100644
--- a/src/api/v1/images.py
+++ b/src/api/v1/images.py
@@ -6,7 +6,7 @@ from bson import ObjectId
 import io
 
 from src.auth.security import get_current_user
-from src.services.image_service import ImageService
+from src.dependencies import ImageServiceDep
 from src.models.user import UserModel
 from src.schemas.image import ImageResponse, ImageListResponse, ImageCreate, ImageUpdate
 from src.utils.logging import log_request
@@ -15,16 +15,14 @@ logger = logging.getLogger(__name__)
 
 router = APIRouter(tags=["Images"], prefix="/images")
 
-# Initialize service
-image_service = ImageService()
-
 @router.post("", response_model=ImageResponse, status_code=201)
 async def upload_image(
     request: Request,
     file: UploadFile = File(..., description="Image file to upload"),
     description: Optional[str] = Query(None, description="Optional description for the image"),
     collection_id: Optional[str] = Query(None, description="Optional collection ID to associate with the image"),
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    image_service: ImageServiceDep = Depends()
 ):
     """
     Upload a new image
@@ -38,6 +36,7 @@ async def upload_image(
         description: Optional description for the image
         collection_id: Optional collection ID to organize the image
         current_user: The authenticated user uploading the image
+        image_service: Injected image service
         
     Returns:
         ImageResponse: The uploaded image metadata and processing status
@@ -79,7 +78,8 @@ async def list_images(
     skip: int = Query(0, ge=0, description="Number of records to skip for pagination"),
     limit: int = Query(50, ge=1, le=100, description="Maximum number of records to return (1-100)"),
     collection_id: Optional[str] = Query(None, description="Filter by collection ID"),
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    image_service: ImageServiceDep = Depends()
 ):
     """
     List images for the current user's team or all images if admin
@@ -92,6 +92,7 @@ async def list_images(
         limit: Maximum number of records to return, 1-100 (default: 50)
         collection_id: Optional filter by collection ID
         current_user: The authenticated user
+        image_service: Injected image service
         
     Returns:
         ImageListResponse: Paginated list of images with metadata
@@ -128,7 +129,8 @@ async def list_images(
 async def get_image(
     image_id: str,
     request: Request,
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    image_service: ImageServiceDep = Depends()
 ):
     """
     Get image metadata by ID
@@ -139,6 +141,7 @@ async def get_image(
     Args:
         image_id: The image ID to retrieve
         current_user: The authenticated user
+        image_service: Injected image service
         
     Returns:
         ImageResponse: Complete image metadata
@@ -181,7 +184,8 @@ async def get_image(
 async def download_image(
     image_id: str,
     request: Request,
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    image_service: ImageServiceDep = Depends()
 ):
     """
     Download image file
@@ -192,6 +196,7 @@ async def download_image(
     Args:
         image_id: The image ID to download
         current_user: The authenticated user
+        image_service: Injected image service
         
     Returns:
         StreamingResponse: The image file as a download
@@ -242,7 +247,8 @@ async def update_image(
     image_id: str,
     image_data: ImageUpdate,
     request: Request,
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    image_service: ImageServiceDep = Depends()
 ):
     """
     Update image metadata
@@ -254,6 +260,7 @@ async def update_image(
         image_id: The image ID to update
         image_data: The image update data
         current_user: The authenticated user
+        image_service: Injected image service
         
     Returns:
         ImageResponse: Updated image metadata
@@ -297,7 +304,8 @@ async def update_image(
 async def delete_image(
     image_id: str,
     request: Request,
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    image_service: ImageServiceDep = Depends()
 ):
     """
     Delete an image
@@ -308,6 +316,7 @@ async def delete_image(
     Args:
         image_id: The image ID to delete
         current_user: The authenticated user
+        image_service: Injected image service
         
     Returns:
         None (204 No Content)
diff --git a/src/api/v1/search.py b/src/api/v1/search.py
index 8dce8a9..1dcc321 100644
--- a/src/api/v1/search.py
+++ b/src/api/v1/search.py
@@ -3,7 +3,7 @@ from typing import Optional, List, Dict, Any
 from fastapi import APIRouter, Depends, Query, Request, HTTPException
 
 from src.auth.security import get_current_user
-from src.services.search_service import SearchService
+from src.dependencies import SearchServiceDep
 from src.models.user import UserModel
 from src.schemas.search import SearchResponse, SearchRequest
 from src.utils.logging import log_request
@@ -12,9 +12,6 @@ logger = logging.getLogger(__name__)
 
 router = APIRouter(tags=["Search"], prefix="/search")
 
-# Initialize service
-search_service = SearchService()
-
 @router.get("", response_model=SearchResponse)
 async def search_images(
     request: Request,
@@ -22,7 +19,8 @@ async def search_images(
     limit: int = Query(10, ge=1, le=50, description="Number of results to return (1-50)"),
     similarity_threshold: float = Query(0.65, ge=0.0, le=1.0, description="Similarity threshold (0.0-1.0)"),
     collection_id: Optional[str] = Query(None, description="Filter results by collection ID"),
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    search_service: SearchServiceDep = Depends()
 ):
     """
     Search for images using semantic similarity
@@ -37,6 +35,7 @@ async def search_images(
         similarity_threshold: Minimum similarity score (0.0-1.0, default: 0.65)
         collection_id: Optional filter to search within a specific collection
         current_user: The authenticated user performing the search
+        search_service: Injected search service
         
     Returns:
         SearchResponse: List of matching images with similarity scores
@@ -84,7 +83,8 @@ async def search_images(
 async def search_images_advanced(
     search_request: SearchRequest,
     request: Request,
-    current_user: UserModel = Depends(get_current_user)
+    current_user: UserModel = Depends(get_current_user),
+    search_service: SearchServiceDep = Depends()
 ):
     """
     Advanced search for images with extended options
@@ -96,6 +96,7 @@ async def search_images_advanced(
     Args:
         search_request: Advanced search request with detailed parameters
         current_user: The authenticated user performing the search
+        search_service: Injected search service
         
     Returns:
         SearchResponse: List of matching images with similarity scores and metadata
diff --git a/src/api/v1/teams.py b/src/api/v1/teams.py
index 558b606..fe5330a 100644
--- a/src/api/v1/teams.py
+++ b/src/api/v1/teams.py
@@ -2,7 +2,7 @@ import logging
 from fastapi import APIRouter, Depends, HTTPException, Request
 from bson import ObjectId
 
-from src.services.team_service import TeamService
+from src.dependencies import TeamServiceDep
 from src.schemas.team import TeamCreate, TeamUpdate, TeamResponse, TeamListResponse
 from src.utils.logging import log_request
 
@@ -10,13 +10,11 @@ logger = logging.getLogger(__name__)
 
 router = APIRouter(tags=["Teams"], prefix="/teams")
 
-# Initialize service
-team_service = TeamService()
-
 @router.post("", response_model=TeamResponse, status_code=201)
 async def create_team(
     team_data: TeamCreate, 
-    request: Request
+    request: Request,
+    team_service: TeamServiceDep = Depends()
 ):
     """
     Create a new team
@@ -26,6 +24,7 @@ async def create_team(
     
     Args:
         team_data: Team creation data including name and description
+        team_service: Injected team service
         
     Returns:
         TeamResponse: The created team information
@@ -50,13 +49,19 @@ async def create_team(
         raise HTTPException(status_code=500, detail="Internal server error")
 
 @router.get("", response_model=TeamListResponse)
-async def list_teams(request: Request):
+async def list_teams(
+    request: Request,
+    team_service: TeamServiceDep = Depends()
+):
     """
     List all teams
     
     Retrieves a complete list of all teams in the system with their
     basic information and member counts.
     
+    Args:
+        team_service: Injected team service
+    
     Returns:
         TeamListResponse: List of all teams with total count
         
@@ -78,7 +83,8 @@ async def list_teams(request: Request):
 @router.get("/{team_id}", response_model=TeamResponse)
 async def get_team(
     team_id: str, 
-    request: Request
+    request: Request,
+    team_service: TeamServiceDep = Depends()
 ):
     """
     Get a team by ID
@@ -88,6 +94,7 @@ async def get_team(
     
     Args:
         team_id: The team ID to retrieve
+        team_service: Injected team service
         
     Returns:
         TeamResponse: Complete team information
@@ -119,7 +126,8 @@ async def get_team(
 async def update_team(
     team_id: str, 
     team_data: TeamUpdate, 
-    request: Request
+    request: Request,
+    team_service: TeamServiceDep = Depends()
 ):
     """
     Update a team
@@ -130,6 +138,7 @@ async def update_team(
     Args:
         team_id: The team ID to update
         team_data: The team update data
+        team_service: Injected team service
         
     Returns:
         TeamResponse: Updated team information
@@ -160,7 +169,8 @@ async def update_team(
 @router.delete("/{team_id}", status_code=204)
 async def delete_team(
     team_id: str, 
-    request: Request
+    request: Request,
+    team_service: TeamServiceDep = Depends()
 ):
     """
     Delete a team
@@ -170,6 +180,7 @@ async def delete_team(
     
     Args:
         team_id: The team ID to delete
+        team_service: Injected team service
         
     Returns:
         None (204 No Content)
diff --git a/src/api/v1/users.py b/src/api/v1/users.py
index db5c3f7..9671f6c 100644
--- a/src/api/v1/users.py
+++ b/src/api/v1/users.py
@@ -2,7 +2,7 @@ import logging
 from typing import Optional
 from fastapi import APIRouter, Depends, HTTPException, Request, Query
 
-from src.services.user_service import UserService
+from src.dependencies import UserServiceDep
 from src.schemas.user import UserResponse, UserListResponse, UserCreate, UserUpdate
 from src.utils.logging import log_request
 
@@ -10,13 +10,11 @@ logger = logging.getLogger(__name__)
 
 router = APIRouter(tags=["Users"], prefix="/users")
 
-# Initialize service
-user_service = UserService()
-
 @router.get("/me", response_model=UserResponse)
 async def read_users_me(
     request: Request,
-    user_id: str = Query(..., description="User ID to retrieve information for")
+    user_id: str = Query(..., description="User ID to retrieve information for"),
+    user_service: UserServiceDep = Depends()
 ):
     """
     Get user information by user ID
@@ -26,6 +24,7 @@ async def read_users_me(
     
     Args:
         user_id: The user ID to retrieve information for
+        user_service: Injected user service
         
     Returns:
         UserResponse: Complete user information including profile data
@@ -57,7 +56,8 @@ async def read_users_me(
 async def update_current_user(
     user_data: UserUpdate,
     request: Request,
-    user_id: str = Query(..., description="User ID to update")
+    user_id: str = Query(..., description="User ID to update"),
+    user_service: UserServiceDep = Depends()
 ):
     """
     Update user information by user ID
@@ -68,6 +68,7 @@ async def update_current_user(
     Args:
         user_data: The user update data containing fields to modify
         user_id: The user ID to update
+        user_service: Injected user service
         
     Returns:
         UserResponse: Updated user information
@@ -98,7 +99,8 @@ async def update_current_user(
 @router.post("", response_model=UserResponse, status_code=201)
 async def create_user(
     user_data: UserCreate,
-    request: Request
+    request: Request,
+    user_service: UserServiceDep = Depends()
 ):
     """
     Create a new user
@@ -108,6 +110,7 @@ async def create_user(
     
     Args:
         user_data: User creation data including name, email, and team assignment
+        user_service: Injected user service
         
     Returns:
         UserResponse: The created user information
@@ -138,7 +141,8 @@ async def create_user(
 @router.get("", response_model=UserListResponse)
 async def list_users(
     request: Request,
-    team_id: Optional[str] = Query(None, description="Filter users by team ID")
+    team_id: Optional[str] = Query(None, description="Filter users by team ID"),
+    user_service: UserServiceDep = Depends()
 ):
     """
     List users with optional team filtering
@@ -148,6 +152,7 @@ async def list_users(
     
     Args:
         team_id: Optional team ID to filter users by
+        user_service: Injected user service
         
     Returns:
         UserListResponse: List of users with total count
@@ -174,7 +179,8 @@ async def list_users(
 @router.get("/{user_id}", response_model=UserResponse)
 async def get_user(
     user_id: str,
-    request: Request
+    request: Request,
+    user_service: UserServiceDep = Depends()
 ):
     """
     Get user by ID
@@ -183,6 +189,7 @@ async def get_user(
     
     Args:
         user_id: The user ID to retrieve
+        user_service: Injected user service
         
     Returns:
         UserResponse: Complete user information
@@ -214,7 +221,8 @@ async def get_user(
 async def update_user(
     user_id: str,
     user_data: UserUpdate,
-    request: Request
+    request: Request,
+    user_service: UserServiceDep = Depends()
 ):
     """
     Update user by ID
@@ -225,6 +233,7 @@ async def update_user(
     Args:
         user_id: The user ID to update
         user_data: The user update data
+        user_service: Injected user service
         
     Returns:
         UserResponse: Updated user information
@@ -255,7 +264,8 @@ async def update_user(
 @router.delete("/{user_id}", status_code=204)
 async def delete_user(
     user_id: str,
-    request: Request
+    request: Request,
+    user_service: UserServiceDep = Depends()
 ):
     """
     Delete user by ID
@@ -264,6 +274,7 @@ async def delete_user(
     
     Args:
         user_id: The user ID to delete
+        user_service: Injected user service
         
     Returns:
         None (204 No Content)
diff --git a/src/dependencies.py b/src/dependencies.py
new file mode 100644
index 0000000..61eafcf
--- /dev/null
+++ b/src/dependencies.py
@@ -0,0 +1,89 @@
+"""
+Dependency injection module for services.
+
+This module provides dependency injection for all services used across the API.
+It follows the dependency injection pattern to improve testability and maintainability.
+"""
+
+from functools import lru_cache
+from typing import Annotated
+from fastapi import Depends
+
+from src.services.auth_service import AuthService
+from src.services.image_service import ImageService
+from src.services.search_service import SearchService
+from src.services.team_service import TeamService
+from src.services.user_service import UserService
+
+
+@lru_cache()
+def get_auth_service() -> AuthService:
+    """
+    Get AuthService instance.
+    
+    Uses LRU cache to ensure singleton behavior for the service instance.
+    
+    Returns:
+        AuthService: The authentication service instance
+    """
+    return AuthService()
+
+
+@lru_cache()
+def get_image_service() -> ImageService:
+    """
+    Get ImageService instance.
+    
+    Uses LRU cache to ensure singleton behavior for the service instance.
+    
+    Returns:
+        ImageService: The image service instance
+    """
+    return ImageService()
+
+
+@lru_cache()
+def get_search_service() -> SearchService:
+    """
+    Get SearchService instance.
+    
+    Uses LRU cache to ensure singleton behavior for the service instance.
+    
+    Returns:
+        SearchService: The search service instance
+    """
+    return SearchService()
+
+
+@lru_cache()
+def get_team_service() -> TeamService:
+    """
+    Get TeamService instance.
+    
+    Uses LRU cache to ensure singleton behavior for the service instance.
+    
+    Returns:
+        TeamService: The team service instance
+    """
+    return TeamService()
+
+
+@lru_cache()
+def get_user_service() -> UserService:
+    """
+    Get UserService instance.
+    
+    Uses LRU cache to ensure singleton behavior for the service instance.
+    
+    Returns:
+        UserService: The user service instance
+    """
+    return UserService()
+
+
+# Type aliases for dependency injection
+AuthServiceDep = Annotated[AuthService, Depends(get_auth_service)]
+ImageServiceDep = Annotated[ImageService, Depends(get_image_service)]
+SearchServiceDep = Annotated[SearchService, Depends(get_search_service)]
+TeamServiceDep = Annotated[TeamService, Depends(get_team_service)]
+UserServiceDep = Annotated[UserService, Depends(get_user_service)] 
\ No newline at end of file