diff --git a/model_bakery/baker.py b/model_bakery/baker.py
index 61e16a97..4051fa9a 100644
--- a/model_bakery/baker.py
+++ b/model_bakery/baker.py
@@ -51,7 +51,7 @@
 
 if BAKER_CONTENTTYPES:
     from django.contrib.contenttypes import models as contenttypes_models
-    from django.contrib.contenttypes.fields import GenericRelation
+    from django.contrib.contenttypes.fields import GenericRelation, GenericForeignKey
 else:
     contenttypes_models = None
     GenericRelation = None
@@ -622,7 +622,7 @@ def _skip_field(self, field: Field) -> bool:  # noqa: C901
 
         if field.name not in self.model_attrs:  # noqa: SIM102
             if field.name not in self.rel_fields and (
-                field.null and not field.fill_optional
+                not field.fill_optional and field.null
             ):
                 return True
 
@@ -702,12 +702,16 @@ def generate_value(self, field: Field, commit: bool = True) -> Any:  # noqa: C90
         model.
         """
         is_content_type_fk = False
+        is_generic_fk = False
         if BAKER_CONTENTTYPES:
             is_content_type_fk = isinstance(field, ForeignKey) and issubclass(
                 self._remote_field(field).model, contenttypes_models.ContentType
             )
+            is_generic_fk = isinstance(field, GenericForeignKey)
+        if is_generic_fk:
+            generator = self.type_mapping[GenericForeignKey]
         # we only use default unless the field is overwritten in `self.rel_fields`
-        if field.has_default() and field.name not in self.rel_fields:
+        elif field.has_default() and field.name not in self.rel_fields:
             if callable(field.default):
                 return field.default()
             return field.default
diff --git a/model_bakery/content_types.py b/model_bakery/content_types.py
index d0d0c880..d530d393 100644
--- a/model_bakery/content_types.py
+++ b/model_bakery/content_types.py
@@ -8,7 +8,10 @@
 
 if BAKER_CONTENTTYPES:
     from django.contrib.contenttypes.models import ContentType
+    from django.contrib.contenttypes.fields import GenericForeignKey
 
     from . import random_gen
 
     default_contenttypes_mapping[ContentType] = random_gen.gen_content_type
+    # a small hack to generate random object for GenericForeignKey
+    default_contenttypes_mapping[GenericForeignKey] = random_gen.gen_content_type
diff --git a/tests/test_filling_fields.py b/tests/test_filling_fields.py
index 6f25f638..d4297a0c 100644
--- a/tests/test_filling_fields.py
+++ b/tests/test_filling_fields.py
@@ -310,6 +310,13 @@ def test_iteratively_filling_generic_foreign_key_field(self):
         assert dummies[1].content_type == expected_content_type
         assert dummies[1].object_id == objects[1].pk
 
+    def test_with_fill_optional(self):
+        from django.contrib.contenttypes.models import ContentType
+
+        dummy = baker.make(models.DummyGenericForeignKeyModel, _fill_optional=True)
+        assert isinstance(dummy.content_type, ContentType)
+        assert dummy.content_type.model_class() is not None
+
 
 @pytest.mark.django_db
 class TestFillingForeignKeyFieldWithDefaultFunctionReturningId: