diff --git a/pydantic/_internal/_generate_schema.py b/pydantic/_internal/_generate_schema.py
index 91c317f766..34f0bd9d25 100644
--- a/pydantic/_internal/_generate_schema.py
+++ b/pydantic/_internal/_generate_schema.py
@@ -702,8 +702,6 @@ def _generate_dc_field_schema(
         )
 
     def _common_field_schema(self, name: str, field_info: FieldInfo, decorators: DecoratorInfos) -> _CommonField:
-        assert field_info.annotation is not None, 'field_info.annotation should not be None when generating a schema'
-
         source_type, annotations = field_info.annotation, field_info.metadata
 
         def set_discriminator(schema: CoreSchema) -> CoreSchema:
diff --git a/tests/test_generics.py b/tests/test_generics.py
index 197267dd37..fbd30abbc2 100644
--- a/tests/test_generics.py
+++ b/tests/test_generics.py
@@ -2477,3 +2477,13 @@ class Model(BaseModel):
         Model(f_value=(1, 'abc'))
     with pytest.raises(ValidationError):
         Model(f_value=('abc', True))
+
+
+def test_generic_none():
+    T = TypeVar('T')
+
+    class Container(BaseModel, Generic[T]):
+        value: T
+
+    assert Container[type(None)](value=None).value is None
+    assert Container[None](value=None).value is None