diff --git a/appyter/execspec/implementations/docker.py b/appyter/execspec/implementations/docker.py
index ac8727e8..91ee74ad 100644
--- a/appyter/execspec/implementations/docker.py
+++ b/appyter/execspec/implementations/docker.py
@@ -71,6 +71,7 @@ async def _run(self, **job):
     async for msg, done in self._submit(**job):
       if not done:
         try: yield await async_json_loads(msg)
+        except asyncio.CancelledError: raise
         except: logger.warning(traceback.format_exc())
     if msg != 0:
       yield dict(type='error', data=f"Container exited with error code")
diff --git a/appyter/ext/asyncio/subprocess.py b/appyter/ext/asyncio/subprocess.py
index aeecb80a..d854f2e2 100644
--- a/appyter/ext/asyncio/subprocess.py
+++ b/appyter/ext/asyncio/subprocess.py
@@ -24,6 +24,15 @@ async def stream_readline_to_queue(stream, queue, chunk_size=65536):
   else:
     await queue.put((None, True))
 
+async def ensure_terminated(proc: asyncio.subprocess.Process):
+  try:
+    if proc.returncode is None:
+      proc.terminate()
+    await asyncio.sleep(5000)
+  finally:
+    if proc.returncode is None:
+      proc.kill()
+
 async def sh(*args, chunk_size=65536, **kwargs):
   ''' An opinionated asyncio shell that logs stderr & yields stdout, done
   Unlike standard create_subprocess_exec: LimitOverrunError should not be possible.
@@ -36,14 +45,19 @@ async def sh(*args, chunk_size=65536, **kwargs):
     limit=chunk_size * 2,
     **kwargs,
   )
-  reader = asyncio.create_task(stream_readline_to_queue(proc.stdout, stdout_queue, chunk_size=chunk_size))
-  while True:
-    msg, done = await stdout_queue.get()
-    if isinstance(msg, bytes):
-      yield msg, False
-    elif isinstance(msg, Exception):
-      raise msg
-    stdout_queue.task_done()
-    if done: break
-  await reader
-  yield await proc.wait(), True
+  try:
+    reader = asyncio.create_task(stream_readline_to_queue(proc.stdout, stdout_queue, chunk_size=chunk_size))
+    while True:
+      msg, done = await stdout_queue.get()
+      if isinstance(msg, bytes):
+        yield msg, False
+      elif isinstance(msg, Exception):
+        raise msg
+      stdout_queue.task_done()
+      if done: break
+    await reader
+    yield await proc.wait(), True
+  except:
+    raise
+  finally:
+    asyncio.create_task(ensure_terminated(proc))
diff --git a/appyter/orchestration/dispatcher/__init__.py b/appyter/orchestration/dispatcher/__init__.py
index 6a2ff61c..e401abf8 100644
--- a/appyter/orchestration/dispatcher/__init__.py
+++ b/appyter/orchestration/dispatcher/__init__.py
@@ -19,6 +19,7 @@ def create_app(**kwargs):
     PROXY=kwargs.get('proxy'),
     JOBS=kwargs.get('jobs'),
     JOBS_PER_IMAGE=kwargs.get('jobs_per_image'),
+    TIMEOUT=kwargs.get('timeout'),
     DEBUG=kwargs.get('debug'),
     PREFIX=kwargs.get('prefix', '').rstrip('/'),
   )
@@ -48,6 +49,7 @@ async def redirect_to_prefix(request):
 @click_option_setenv('--proxy', envvar='APPYTER_PROXY', type=bool, default=False, help='Whether this is running behind a proxy and the IP should be fixed for CORS')
 @click_option_setenv('--jobs', envvar='APPYTER_JOBS', type=int, default=2, help='Number of concurrent jobs to dispatch')
 @click_option_setenv('--jobs-per-image', envvar='APPYTER_JOBS_PER_IMAGE', type=int, default=1, help='Number of concurrent jobs to dispatch for any individual appyter image')
+@click_option_setenv('--timeout', envvar='APPYTER_TIMEOUT', type=float, default=None, help='How long in seconds a job can run before it is cancelled')
 @click_option_setenv('--debug', envvar='APPYTER_DEBUG', type=bool, default=True, help='Whether or not we should be in debugging mode, not for use in multi-tenant situations')
 def dispatcher(*args, **kwargs):
   from appyter.ext.aiohttp import run_app
diff --git a/appyter/orchestration/dispatcher/core.py b/appyter/orchestration/dispatcher/core.py
index bfc8ad0a..d323dbc6 100644
--- a/appyter/orchestration/dispatcher/core.py
+++ b/appyter/orchestration/dispatcher/core.py
@@ -40,6 +40,7 @@ async def dispatcher_ctx(app):
   #
   app['dispatch_queue'] = asyncio.Queue()
   app['tasks'] = LockedOrderedDict()
+  timeout = app['config']['TIMEOUT']
   #
   logger.info('Starting background tasks...')
   tasks = [
@@ -48,6 +49,7 @@ async def dispatcher_ctx(app):
         queued=app['dispatch_queue'],
         tasks=app['tasks'],
         jobs_per_image=app['config']['JOBS_PER_IMAGE'],
+        timeout=timeout,
       )
     )
     for _ in range(app['config']['JOBS'])
@@ -69,7 +71,16 @@ async def slow_put(queue, item):
   await asyncio.sleep(0.5 + random.random())
   await queue.put(item)
 
-async def dispatcher(queued=None, tasks=None, jobs_per_image=1):
+async def dispatch(job_id, job):
+  from appyter.ext.emitter import url_to_emitter
+  from appyter.execspec.core import url_to_executor
+  async with url_to_executor(job['executor']) as executor:
+    async with url_to_emitter(job['url']) as emitter:
+      logger.info(f"Dispatching job {job_id}")
+      async for msg in executor._run(**job):
+        await emitter(msg)
+
+async def dispatcher(queued=None, tasks=None, jobs_per_image=1, timeout=None):
   while True:
     job_id = await queued.get()
     async with tasks.lock:
@@ -87,13 +98,7 @@ async def dispatcher(queued=None, tasks=None, jobs_per_image=1):
         ).isoformat()
     #
     try:
-      from appyter.ext.emitter import url_to_emitter
-      from appyter.execspec.core import url_to_executor
-      async with url_to_executor(job['executor']) as executor:
-        async with url_to_emitter(job['url']) as emitter:
-          logger.info(f"Dispatching job {job_id}")
-          async for msg in executor._run(**job):
-            await emitter(msg)
+      await asyncio.wait_for(dispatch(job_id, job), timeout=timeout)
     except asyncio.CancelledError:
       raise
     except: