diff --git a/django/core/checks/__init__.py b/django/core/checks/__init__.py
index ededae38ba..b987af7bf5 100644
--- a/django/core/checks/__init__.py
+++ b/django/core/checks/__init__.py
@@ -5,6 +5,7 @@ from .messages import (
 from .registry import Tags, register, run_checks, tag_exists
 
 # Import these to force registration of checks
+import django.core.checks.asyncio  # NOQA isort:skip
 import django.core.checks.caches  # NOQA isort:skip
 import django.core.checks.database  # NOQA isort:skip
 import django.core.checks.model_checks  # NOQA isort:skip
diff --git a/django/core/checks/asyncio.py b/django/core/checks/asyncio.py
new file mode 100644
index 0000000000..2063481bd6
--- /dev/null
+++ b/django/core/checks/asyncio.py
@@ -0,0 +1,16 @@
+import os
+
+from . import Error, Tags, register
+
+E001 = Error(
+    "You must not set DJANGO_ALLOW_ASYNC_UNSAFE in your "
+    "deployment environment variable",
+    id='asyncio.E001',
+)
+
+
+@register(Tags.asyncio, deploy=True)
+def check_async_unsafe(app_configs, **kwargs):
+    if os.environ.get('DJANGO_ALLOW_ASYNC_UNSAFE'):
+        return [E001]
+    return []
diff --git a/django/core/checks/registry.py b/django/core/checks/registry.py
index 74359db586..f81a0197f9 100644
--- a/django/core/checks/registry.py
+++ b/django/core/checks/registry.py
@@ -8,6 +8,7 @@ class Tags:
     Built-in tags for internal checks.
     """
     admin = 'admin'
+    asyncio = 'asyncio'
     caches = 'caches'
     compatibility = 'compatibility'
     database = 'database'
diff --git a/tests/check_framework/test_asyncio.py b/tests/check_framework/test_asyncio.py
new file mode 100644
index 0000000000..5158d29b49
--- /dev/null
+++ b/tests/check_framework/test_asyncio.py
@@ -0,0 +1,16 @@
+import os
+from unittest import mock
+
+from django.core.checks import asyncio
+from django.test import SimpleTestCase
+
+
+class CheckAsynchronousSafetyTest(SimpleTestCase):
+    @property
+    def func(self):
+        from django.core.checks.asyncio import check_async_unsafe
+        return check_async_unsafe
+
+    @mock.patch.dict(os.environ, {'DJANGO_ALLOW_ASYNC_UNSAFE': 'true'})
+    def test_not_allowed_async_unsafe(self):
+        self.assertEqual(self.func(None), [asyncio.E001])