diff --git a/homeassistant/helpers/config_validation.py b/homeassistant/helpers/config_validation.py
index bd5d85230c5..40b06447a2f 100644
--- a/homeassistant/helpers/config_validation.py
+++ b/homeassistant/helpers/config_validation.py
@@ -549,7 +549,13 @@ def deprecated(key: str,
         - Once the invalidation_version is crossed, raises vol.Invalid if key
         is detected
     """
-    module_name = inspect.getmodule(inspect.stack()[1][0]).__name__
+    module = inspect.getmodule(inspect.stack()[1][0])
+    if module is not None:
+        module_name = module.__name__
+    else:
+        # Unclear when it is None, but it happens, so let's guard.
+        # https://github.com/home-assistant/home-assistant/issues/24982
+        module_name = __name__
 
     if replacement_key and invalidation_version:
         warning = ("The '{key}' option (with value '{value}') is"
diff --git a/tests/helpers/test_config_validation.py b/tests/helpers/test_config_validation.py
index 6124699d88e..a4513dbab19 100644
--- a/tests/helpers/test_config_validation.py
+++ b/tests/helpers/test_config_validation.py
@@ -833,6 +833,16 @@ def test_deprecated_with_replacement_key_invalidation_version_default(
             "invalid in version 0.1.0") == str(exc_info.value)
 
 
+def test_deprecated_cant_find_module():
+    """Test if the current module cannot be inspected."""
+    with patch('inspect.getmodule', return_value=None):
+        # This used to raise.
+        cv.deprecated(
+            'mars', replacement_key='jupiter', invalidation_version='1.0.0',
+            default=False
+        )
+
+
 def test_key_dependency():
     """Test key_dependency validator."""
     schema = vol.Schema(cv.key_dependency('beer', 'soda'))