diff --git a/sagemaker-core/src/sagemaker/core/workflow/utilities.py b/sagemaker-core/src/sagemaker/core/workflow/utilities.py
index c07a31c51e..88ac23a533 100644
--- a/sagemaker-core/src/sagemaker/core/workflow/utilities.py
+++ b/sagemaker-core/src/sagemaker/core/workflow/utilities.py
@@ -210,6 +210,12 @@ def get_processing_code_hash(code: str, source_dir: str, dependencies: List[str]
         str: A hash string representing the unique code artifact(s) for the step
     """
 
+    # SourceCode.requirements and other upstream dependency fields default to None
+    # when not explicitly set. Since this function concatenates dependencies via list
+    # addition (e.g. [source_dir] + dependencies), we default None to an empty list
+    # to prevent TypeError.
+    dependencies = dependencies or []
+
     # FrameworkProcessor
     if source_dir:
         source_dir_url = urlparse(source_dir)
diff --git a/sagemaker-core/tests/unit/workflow/test_utilities.py b/sagemaker-core/tests/unit/workflow/test_utilities.py
index 5e9ed7bbbd..119379983d 100644
--- a/sagemaker-core/tests/unit/workflow/test_utilities.py
+++ b/sagemaker-core/tests/unit/workflow/test_utilities.py
@@ -214,6 +214,33 @@ def test_get_processing_dependencies_multiple_lists(self):
 
         assert result == ["dep1", "dep2", "dep3", "dep4", "dep5"]
 
+    def test_get_processing_code_hash_with_none_dependencies_and_code_only(self):
+        """Test get_processing_code_hash with None dependencies and code only"""
+        with tempfile.NamedTemporaryFile(mode="w", suffix=".py", delete=False) as f:
+            f.write("print('hello')")
+            temp_file = f.name
+
+        try:
+            result = get_processing_code_hash(code=temp_file, source_dir=None, dependencies=None)
+
+            assert result is not None
+            assert len(result) == 64
+        finally:
+            os.unlink(temp_file)
+
+    def test_get_processing_code_hash_with_none_dependencies_and_source_dir(self):
+        """Test get_processing_code_hash with None dependencies and source_dir"""
+        with tempfile.TemporaryDirectory() as temp_dir:
+            code_file = Path(temp_dir, "script.py")
+            code_file.write_text("print('hello')")
+
+            result = get_processing_code_hash(
+                code=str(code_file), source_dir=temp_dir, dependencies=None
+            )
+
+            assert result is not None
+            assert len(result) == 64
+
     def test_get_processing_code_hash_with_source_dir(self):
         """Test get_processing_code_hash with source_dir"""
         with tempfile.TemporaryDirectory() as temp_dir:
@@ -264,6 +291,35 @@ def test_get_processing_code_hash_with_dependencies(self):
 
             assert result is not None
 
+    def test_get_training_code_hash_with_none_dependencies_and_source_dir(self):
+        """Test get_training_code_hash with None dependencies and source_dir"""
+        with tempfile.TemporaryDirectory() as temp_dir:
+            entry_file = Path(temp_dir, "train.py")
+            entry_file.write_text("print('training')")
+
+            result = get_training_code_hash(
+                entry_point=str(entry_file), source_dir=temp_dir, dependencies=None
+            )
+
+            assert result is not None
+            assert len(result) == 64
+
+    def test_get_training_code_hash_with_none_dependencies_and_entry_point(self):
+        """Test get_training_code_hash with None dependencies and entry_point only"""
+        with tempfile.NamedTemporaryFile(mode="w", suffix=".py", delete=False) as f:
+            f.write("print('training')")
+            temp_file = f.name
+
+        try:
+            result = get_training_code_hash(
+                entry_point=temp_file, source_dir=None, dependencies=None
+            )
+
+            assert result is not None
+            assert len(result) == 64
+        finally:
+            os.unlink(temp_file)
+
     def test_get_training_code_hash_with_source_dir(self):
         """Test get_training_code_hash with source_dir"""
         with tempfile.TemporaryDirectory() as temp_dir: