diff --git a/python/ray/serve/schema.py b/python/ray/serve/schema.py
index 80ed4e9a3..cf1b34f59 100644
--- a/python/ray/serve/schema.py
+++ b/python/ray/serve/schema.py
@@ -8,7 +8,7 @@ from ray.serve.utils import DEFAULT
 
 class RayActorOptionsSchema(BaseModel, extra=Extra.forbid):
     runtime_env: dict = Field(
-        default=None,
+        default={},
         description=(
             "This deployment's runtime_env. working_dir and "
             "py_modules may contain only remote URIs."
@@ -48,7 +48,7 @@ class RayActorOptionsSchema(BaseModel, extra=Extra.forbid):
         ge=0,
     )
     resources: Dict = Field(
-        default=None, description=("The custom resources required by each replica.")
+        default={}, description=("The custom resources required by each replica.")
     )
     accelerator_type: str = Field(
         default=None,
@@ -341,7 +341,7 @@ def schema_to_deployment(s: DeploymentSchema) -> Deployment:
     if s.ray_actor_options is None:
         ray_actor_options = None
     else:
-        ray_actor_options = s.ray_actor_options.dict()
+        ray_actor_options = s.ray_actor_options.dict(exclude_unset=True)
 
     return deployment(
         name=s.name,
diff --git a/python/ray/serve/tests/test_schema.py b/python/ray/serve/tests/test_schema.py
index 28d99183f..37cc7b9d4 100644
--- a/python/ray/serve/tests/test_schema.py
+++ b/python/ray/serve/tests/test_schema.py
@@ -61,7 +61,7 @@ class TestRayActorOptionsSchema:
         # Test different runtime_env configurations
 
         ray_actor_options_schema = {
-            "runtime_env": None,
+            "runtime_env": {},
             "num_cpus": 0.2,
             "num_gpus": 50,
             "memory": 3,
@@ -107,12 +107,12 @@ class TestRayActorOptionsSchema:
         # Undefined fields should be forbidden in the schema
 
         ray_actor_options_schema = {
-            "runtime_env": None,
+            "runtime_env": {},
             "num_cpus": None,
             "num_gpus": None,
             "memory": None,
             "object_store_memory": None,
-            "resources": None,
+            "resources": {},
             "accelerator_type": None,
         }
 
@@ -124,6 +124,15 @@ class TestRayActorOptionsSchema:
         with pytest.raises(ValidationError):
             RayActorOptionsSchema.parse_obj(ray_actor_options_schema)
 
+    def test_dict_defaults_ray_actor_options(self):
+        # Dictionary fields should have empty dictionaries as defaults, not None
+
+        ray_actor_options_schema = {}
+        schema = RayActorOptionsSchema.parse_obj(ray_actor_options_schema)
+        d = schema.dict()
+        assert d["runtime_env"] == {}
+        assert d["resources"] == {}
+
 
 class TestDeploymentSchema:
     def get_minimal_deployment_schema(self):
@@ -144,12 +153,12 @@ class TestDeploymentSchema:
             "health_check_period_s": None,
             "health_check_timeout_s": None,
             "ray_actor_options": {
-                "runtime_env": None,
+                "runtime_env": {},
                 "num_cpus": None,
                 "num_gpus": None,
                 "memory": None,
                 "object_store_memory": None,
-                "resources": None,
+                "resources": {},
                 "accelerator_type": None,
             },
         }
@@ -372,12 +381,12 @@ class TestServeApplicationSchema:
                     "health_check_period_s": None,
                     "health_check_timeout_s": None,
                     "ray_actor_options": {
-                        "runtime_env": None,
+                        "runtime_env": {},
                         "num_cpus": None,
                         "num_gpus": None,
                         "memory": None,
                         "object_store_memory": None,
-                        "resources": None,
+                        "resources": {},
                         "accelerator_type": None,
                     },
                 },
@@ -543,6 +552,24 @@ def test_deployment_to_schema_to_deployment():
     serve.shutdown()
 
 
+def test_unset_fields_schema_to_deployment_ray_actor_options():
+    # Ensure unset fields are excluded from ray_actor_options
+
+    @serve.deployment(
+        num_replicas=3,
+        route_prefix="/hello",
+        ray_actor_options={},
+    )
+    def f():
+        pass
+
+    f._func_or_class = "ray.serve.tests.test_schema.global_f"
+
+    deployment = schema_to_deployment(deployment_to_schema(f))
+
+    assert len(deployment.ray_actor_options) == 0
+
+
 def test_serve_application_to_schema_to_serve_application():
     @serve.deployment(
         num_replicas=1,