diff --git a/homeassistant/helpers/config_validation.py b/homeassistant/helpers/config_validation.py
index bb4dcf6a55f..9ce4b6b166d 100644
--- a/homeassistant/helpers/config_validation.py
+++ b/homeassistant/helpers/config_validation.py
@@ -335,9 +335,12 @@ def slugify(value):
 
 def string(value: Any) -> str:
     """Coerce value to string, except for None."""
-    if value is not None:
-        return str(value)
-    raise vol.Invalid('string value is None')
+    if value is None:
+        raise vol.Invalid('string value is None')
+    if isinstance(value, (list, dict)):
+        raise vol.Invalid('value should be a string')
+
+    return str(value)
 
 
 def temperature_unit(value) -> str:
diff --git a/tests/helpers/test_config_validation.py b/tests/helpers/test_config_validation.py
index ab575c61789..cfd84dbc3b3 100644
--- a/tests/helpers/test_config_validation.py
+++ b/tests/helpers/test_config_validation.py
@@ -356,9 +356,15 @@ def test_string():
     """Test string validation."""
     schema = vol.Schema(cv.string)
 
-    with pytest.raises(vol.MultipleInvalid):
+    with pytest.raises(vol.Invalid):
         schema(None)
 
+    with pytest.raises(vol.Invalid):
+        schema([])
+
+    with pytest.raises(vol.Invalid):
+        schema({})
+
     for value in (True, 1, 'hello'):
         schema(value)