diff --git a/src/crewai/cli/constants.py b/src/crewai/cli/constants.py
index 306f1108b..9ec641dd8 100644
--- a/src/crewai/cli/constants.py
+++ b/src/crewai/cli/constants.py
@@ -103,6 +103,12 @@ ENV_VARS = {
             "key_name": "SAMBANOVA_API_KEY",
         }
     ],
+    "deepseek": [
+        {
+            "prompt": "Enter your DeepSeek API key (press Enter to skip)",
+            "key_name": "DEEPSEEK_API_KEY",
+        }
+    ],
 }
 
 
@@ -119,6 +125,7 @@ PROVIDERS = [
     "azure",
     "cerebras",
     "sambanova",
+    "deepseek",
 ]
 
 MODELS = {
@@ -314,6 +321,13 @@ MODELS = {
         "sambanova/Meta-Llama-3.2-3B-Instruct",
         "sambanova/Meta-Llama-3.2-1B-Instruct",
     ],
+    "deepseek": [
+        "deepseek/deepseek-chat",
+        "deepseek/deepseek-coder",
+        "deepseek/deepseek-r1",
+        "deepseek/deepseek-v3",
+        "deepseek/deepseek-reasoner",
+    ],
 }
 
 DEFAULT_LLM_MODEL = "gpt-4o-mini"
diff --git a/src/crewai/llm.py b/src/crewai/llm.py
index 88edb5ec5..6b069a215 100644
--- a/src/crewai/llm.py
+++ b/src/crewai/llm.py
@@ -154,6 +154,11 @@ LLM_CONTEXT_WINDOW_SIZES = {
     "gemini/gemma-3-27b-it": 128000,
     # deepseek
     "deepseek-chat": 128000,
+    "deepseek/deepseek-chat": 128000,
+    "deepseek/deepseek-coder": 128000,
+    "deepseek/deepseek-r1": 128000,
+    "deepseek/deepseek-v3": 128000,
+    "deepseek/deepseek-reasoner": 128000,
     # groq
     "gemma2-9b-it": 8192,
     "gemma-7b-it": 8192,
diff --git a/tests/test_deepseek_integration.py b/tests/test_deepseek_integration.py
new file mode 100644
index 000000000..0c3b2d06d
--- /dev/null
+++ b/tests/test_deepseek_integration.py
@@ -0,0 +1,115 @@
+"""Tests for DeepSeek integration in CrewAI."""
+
+import pytest
+from unittest.mock import patch, MagicMock
+
+from crewai.llm import LLM
+from crewai.cli.constants import ENV_VARS, PROVIDERS, MODELS
+
+
+class TestDeepSeekIntegration:
+    """Test DeepSeek integration in CrewAI."""
+
+    def test_deepseek_in_providers(self):
+        """Test that DeepSeek is included in the providers list."""
+        assert "deepseek" in PROVIDERS
+
+    def test_deepseek_in_env_vars(self):
+        """Test that DeepSeek API key configuration is in ENV_VARS."""
+        assert "deepseek" in ENV_VARS
+        deepseek_config = ENV_VARS["deepseek"]
+        assert len(deepseek_config) == 1
+        assert deepseek_config[0]["key_name"] == "DEEPSEEK_API_KEY"
+        assert "DeepSeek API key" in deepseek_config[0]["prompt"]
+
+    def test_deepseek_in_models(self):
+        """Test that DeepSeek models are included in the models dictionary."""
+        assert "deepseek" in MODELS
+        deepseek_models = MODELS["deepseek"]
+        expected_models = [
+            "deepseek/deepseek-chat",
+            "deepseek/deepseek-coder",
+            "deepseek/deepseek-r1",
+            "deepseek/deepseek-v3",
+            "deepseek/deepseek-reasoner",
+        ]
+        for model in expected_models:
+            assert model in deepseek_models
+
+    def test_llm_creation_with_deepseek_chat(self):
+        """Test creating LLM instance with deepseek-chat model."""
+        llm = LLM(model="deepseek-chat")
+        assert llm.model == "deepseek-chat"
+        assert llm.get_context_window_size() > 0
+
+    def test_llm_creation_with_deepseek_prefix(self):
+        """Test creating LLM instance with deepseek/ prefix."""
+        llm = LLM(model="deepseek/deepseek-chat")
+        assert llm.model == "deepseek/deepseek-chat"
+        assert llm._get_custom_llm_provider() == "deepseek"
+        assert llm.get_context_window_size() > 0
+
+    def test_deepseek_context_window_sizes(self):
+        """Test that all DeepSeek models have context window sizes defined."""
+        from crewai.llm import LLM_CONTEXT_WINDOW_SIZES
+        
+        deepseek_models = [
+            "deepseek-chat",
+            "deepseek/deepseek-chat",
+            "deepseek/deepseek-coder",
+            "deepseek/deepseek-r1",
+            "deepseek/deepseek-v3",
+            "deepseek/deepseek-reasoner",
+        ]
+        
+        for model in deepseek_models:
+            assert model in LLM_CONTEXT_WINDOW_SIZES
+            assert LLM_CONTEXT_WINDOW_SIZES[model] > 0
+
+    def test_deepseek_models_context_window_consistency(self):
+        """Test that DeepSeek models have consistent context window sizes."""
+        from crewai.llm import LLM_CONTEXT_WINDOW_SIZES
+        
+        expected_size = 128000
+        deepseek_models = [
+            "deepseek-chat",
+            "deepseek/deepseek-chat",
+            "deepseek/deepseek-coder",
+            "deepseek/deepseek-r1",
+            "deepseek/deepseek-v3",
+            "deepseek/deepseek-reasoner",
+        ]
+        
+        for model in deepseek_models:
+            assert LLM_CONTEXT_WINDOW_SIZES[model] == expected_size
+
+    @patch.dict("os.environ", {"DEEPSEEK_API_KEY": "test-key"})
+    def test_llm_with_deepseek_api_key(self):
+        """Test LLM creation with DeepSeek API key in environment."""
+        llm = LLM(model="deepseek/deepseek-chat")
+        assert llm.model == "deepseek/deepseek-chat"
+        assert llm._get_custom_llm_provider() == "deepseek"
+
+    def test_deepseek_provider_detection(self):
+        """Test that DeepSeek provider is correctly detected from model name."""
+        llm = LLM(model="deepseek/deepseek-chat")
+        provider = llm._get_custom_llm_provider()
+        assert provider == "deepseek"
+
+    def test_deepseek_vs_openrouter_provider_detection(self):
+        """Test provider detection for DeepSeek vs OpenRouter DeepSeek models."""
+        deepseek_llm = LLM(model="deepseek/deepseek-chat")
+        openrouter_llm = LLM(model="openrouter/deepseek/deepseek-chat")
+        
+        assert deepseek_llm._get_custom_llm_provider() == "deepseek"
+        assert openrouter_llm._get_custom_llm_provider() == "openrouter"
+
+    def test_all_deepseek_models_can_be_instantiated(self):
+        """Test that all DeepSeek models in MODELS can be instantiated."""
+        deepseek_models = MODELS["deepseek"]
+        
+        for model in deepseek_models:
+            llm = LLM(model=model)
+            assert llm.model == model
+            assert llm._get_custom_llm_provider() == "deepseek"
+            assert llm.get_context_window_size() > 0