diff --git a/app/src/promptforge/providers/openai.py b/app/src/promptforge/providers/openai.py
new file mode 100644
index 0000000..9d404d5
--- /dev/null
+++ b/app/src/promptforge/providers/openai.py
@@ -0,0 +1,149 @@
+import time
+from typing import AsyncIterator, Optional
+
+from openai import AsyncOpenAI, APIError, RateLimitError, APIConnectionError
+
+from .base import ProviderBase, ProviderResponse
+from ..core.exceptions import ProviderError
+
+
+class OpenAIProvider(ProviderBase):
+    """OpenAI GPT models provider."""
+
+    def __init__(
+        self,
+        api_key: Optional[str] = None,
+        model: str = "gpt-4",
+        temperature: float = 0.7,
+        base_url: Optional[str] = None,
+        **kwargs,
+    ):
+        """Initialize OpenAI provider."""
+        super().__init__(api_key, model, temperature, **kwargs)
+        self.base_url = base_url
+        self._client: Optional[AsyncOpenAI] = None
+
+    @property
+    def name(self) -> str:
+        return "openai"
+
+    def _get_client(self) -> AsyncOpenAI:
+        """Get or create OpenAI client."""
+        if self._client is None:
+            api_key = self.api_key or self._get_api_key_from_env()
+            if not api_key:
+                raise ProviderError(
+                    "OpenAI API key not configured. "
+                    "Set OPENAI_API_KEY env var or pass api_key parameter."
+                )
+            self._client = AsyncOpenAI(
+                api_key=api_key,
+                base_url=self.base_url,
+            )
+        return self._client
+
+    def _get_api_key_from_env(self) -> Optional[str]:
+        import os
+        return os.environ.get("OPENAI_API_KEY")
+
+    async def complete(
+        self,
+        prompt: str,
+        system_prompt: Optional[str] = None,
+        max_tokens: Optional[int] = None,
+        **kwargs,
+    ) -> ProviderResponse:
+        """Send completion request to OpenAI."""
+        start_time = time.time()
+
+        try:
+            client = self._get_client()
+
+            messages = []
+            if system_prompt:
+                messages.append({"role": "system", "content": system_prompt})
+            messages.append({"role": "user", "content": prompt})
+
+            response = await client.chat.completions.create(  # type: ignore[arg-type]
+                model=self.model,
+                messages=messages,  # type: ignore[union-attr]
+                temperature=self.temperature,
+                max_tokens=max_tokens,
+                **kwargs,
+            )
+
+            latency_ms = (time.time() - start_time) * 1000
+
+            return ProviderResponse(
+                content=response.choices[0].message.content or "",
+                model=self.model,
+                provider=self.name,
+                usage={
+                    "prompt_tokens": response.usage.prompt_tokens,  # type: ignore[union-attr]
+                    "completion_tokens": response.usage.completion_tokens,  # type: ignore[union-attr]
+                    "total_tokens": response.usage.total_tokens,  # type: ignore[union-attr]
+                },
+                latency_ms=latency_ms,
+                metadata={
+                    "finish_reason": response.choices[0].finish_reason,
+                },
+            )
+        except APIError as e:
+            raise ProviderError(f"OpenAI API error: {e}")
+        except RateLimitError as e:
+            raise ProviderError(f"OpenAI rate limit exceeded: {e}")
+        except APIConnectionError as e:
+            raise ProviderError(f"OpenAI connection error: {e}")
+
+    async def stream_complete(  # type: ignore[override]
+        self,
+        prompt: str,
+        system_prompt: Optional[str] = None,
+        max_tokens: Optional[int] = None,
+        **kwargs,
+    ) -> AsyncIterator[str]:
+        """Stream completion from OpenAI."""
+        try:
+            client = self._get_client()
+
+            messages = []
+            if system_prompt:
+                messages.append({"role": "system", "content": system_prompt})
+            messages.append({"role": "user", "content": prompt})
+
+            stream = await client.chat.completions.create(  # type: ignore[arg-type]
+                model=self.model,
+                messages=messages,  # type: ignore[union-attr]
+                temperature=self.temperature,
+                max_tokens=max_tokens,
+                stream=True,
+                **kwargs,
+            )
+
+            async for chunk in stream:  # type: ignore[union-attr]
+                if chunk.choices[0].delta.content:
+                    yield chunk.choices[0].delta.content
+        except APIError as e:
+            raise ProviderError(f"OpenAI API error: {e}")
+
+    def validate_api_key(self) -> bool:
+        """Validate OpenAI API key."""
+        try:
+            import os
+            api_key = self.api_key or os.environ.get("OPENAI_API_KEY")
+            if not api_key:
+                return False
+            _ = AsyncOpenAI(api_key=api_key)
+            return True
+        except Exception:
+            return False
+
+    def list_models(self) -> list[str]:
+        """List available OpenAI models."""
+        return [
+            "gpt-4",
+            "gpt-4-turbo",
+            "gpt-4o",
+            "gpt-3.5-turbo",
+            "gpt-3.5-turbo-16k",
+        ]