diff --git a/src/noteburst/exceptions.py b/src/noteburst/exceptions.py
index 10a788d..429c3c1 100644
--- a/src/noteburst/exceptions.py
+++ b/src/noteburst/exceptions.py
@@ -11,6 +11,7 @@
 __all__ = [
     "TaskError",
     "NbexecTaskError",
+    "NbexecTaskTimeoutError",
     "NoteburstClientRequestError",
     "NoteburstError",
 ]
@@ -38,6 +39,14 @@ class NbexecTaskError(TaskError):
     task_name = "nbexec"
 
 
+class NbexecTaskTimeoutError(NbexecTaskError):
+    """Error raised when a notebook execution task times out."""
+
+    @classmethod
+    def from_exception(cls, exc: Exception) -> Self:
+        return cls(f"{cls.task_name} timeout error\n\n{exc!s}")
+
+
 class NoteburstClientRequestError(ClientRequestError):
     """Error related to the API client."""
 
diff --git a/src/noteburst/handlers/v1/handlers.py b/src/noteburst/handlers/v1/handlers.py
index 8760e89..4907b55 100644
--- a/src/noteburst/handlers/v1/handlers.py
+++ b/src/noteburst/handlers/v1/handlers.py
@@ -68,6 +68,7 @@ async def post_nbexec(
         ipynb=request_data.get_ipynb_as_str(),
         kernel_name=request_data.kernel_name,
         enable_retry=request_data.enable_retry,
+        timeout=request_data.timeout,
     )
     logger.info("Finished enqueing an nbexec task", job_id=job_metadata.id)
     response_data = await NotebookResponse.from_job_metadata(
diff --git a/src/noteburst/handlers/v1/models.py b/src/noteburst/handlers/v1/models.py
index fd3b211..ee77667 100644
--- a/src/noteburst/handlers/v1/models.py
+++ b/src/noteburst/handlers/v1/models.py
@@ -3,13 +3,14 @@
 from __future__ import annotations
 
 import json
-from datetime import datetime
+from datetime import datetime, timedelta
 from typing import Annotated, Any
 
 from arq.jobs import JobStatus
 from fastapi import Request
 from pydantic import AnyHttpUrl, BaseModel, Field
 from safir.arq import JobMetadata, JobResult
+from safir.pydantic import HumanTimedelta
 
 from noteburst.jupyterclient.jupyterlab import (
     NotebookExecutionErrorModel,
@@ -172,6 +173,17 @@ class PostNotebookRequest(BaseModel):
 
     kernel_name: Annotated[str, kernel_name_field]
 
+    timeout: HumanTimedelta = Field(
+        default_factory=lambda: timedelta(seconds=300),
+        title="Timeout for notebook execution.",
+        description=(
+            "The timeout is is a human-readable duration string. For "
+            "example, '5m' is 5 minutes, '1h' is 1 hour, '1d' is 1 day."
+            "If the notebook execution does not complete within this time,"
+            "the job is marked as failed."
+        ),
+    )
+
     enable_retry: Annotated[
         bool,
         Field(
diff --git a/src/noteburst/worker/functions/nbexec.py b/src/noteburst/worker/functions/nbexec.py
index c008edc..74230bc 100644
--- a/src/noteburst/worker/functions/nbexec.py
+++ b/src/noteburst/worker/functions/nbexec.py
@@ -4,14 +4,16 @@
 
 from __future__ import annotations
 
+import asyncio
 import json
 import sys
+from datetime import timedelta
 from typing import Any, cast
 
 from arq import Retry
 from safir.slack.blockkit import SlackCodeBlock, SlackTextField
 
-from noteburst.exceptions import NbexecTaskError
+from noteburst.exceptions import NbexecTaskError, NbexecTaskTimeoutError
 from noteburst.jupyterclient.jupyterlab import JupyterClient, JupyterError
 
 
@@ -21,6 +23,7 @@ async def nbexec(
     ipynb: str,
     kernel_name: str = "LSST",
     enable_retry: bool = True,
+    timeout: timedelta | None = None,  # noqa: ASYNC109
 ) -> str:
     """Execute a notebook, as an asynchronous arq worker task.
 
@@ -54,10 +57,15 @@ async def nbexec(
     parsed_notebook = json.loads(ipynb)
     logger.debug("Got ipynb", ipynb=parsed_notebook)
     try:
-        execution_result = await jupyter_client.execute_notebook(
-            parsed_notebook, kernel_name=kernel_name
+        execution_result = await asyncio.wait_for(
+            jupyter_client.execute_notebook(
+                parsed_notebook, kernel_name=kernel_name
+            ),
+            timeout=timeout.total_seconds() if timeout else None,
         )
         logger.info("nbexec finished", error=execution_result.error)
+    except TimeoutError as e:
+        raise NbexecTaskTimeoutError.from_exception(e) from e
     except JupyterError as e:
         logger.exception("nbexec error", jupyter_status=e.status)
         if "slack" in ctx and "slack_message_factory" in ctx: