diff --git a/rest_framework/decorators.py b/rest_framework/decorators.py
index 3020edc16..62afa0597 100644
--- a/rest_framework/decorators.py
+++ b/rest_framework/decorators.py
@@ -130,7 +130,7 @@ def schema(view_inspector):
     return decorator
 
 
-def action(methods=None, detail=True, url_path=None, url_name=None, **kwargs):
+def action(methods=None, detail=None, url_path=None, url_name=None, **kwargs):
     """
     Mark a ViewSet method as a routable action.
 
@@ -140,6 +140,10 @@ def action(methods=None, detail=True, url_path=None, url_name=None, **kwargs):
     methods = ['get'] if (methods is None) else methods
     methods = [method.lower() for method in methods]
 
+    assert detail is not None, (
+        "@action() missing required argument: 'detail'"
+    )
+
     def decorator(func):
         func.bind_to_methods = methods
         func.detail = detail
diff --git a/tests/test_decorators.py b/tests/test_decorators.py
index a86cb5a3e..674990730 100644
--- a/tests/test_decorators.py
+++ b/tests/test_decorators.py
@@ -173,7 +173,7 @@ class DecoratorTestCase(TestCase):
 class ActionDecoratorTestCase(TestCase):
 
     def test_defaults(self):
-        @action()
+        @action(detail=True)
         def test_action(request):
             pass
 
@@ -182,6 +182,14 @@ class ActionDecoratorTestCase(TestCase):
         assert test_action.url_path == 'test_action'
         assert test_action.url_name == 'test-action'
 
+    def test_detail_required(self):
+        with pytest.raises(AssertionError) as excinfo:
+            @action()
+            def test_action(request):
+                pass
+
+        assert str(excinfo.value) == "@action() missing required argument: 'detail'"
+
     def test_detail_route_deprecation(self):
         with pytest.warns(PendingDeprecationWarning) as record:
             @detail_route()