diff --git a/moto/awslambda/models.py b/moto/awslambda/models.py
index a26fcba40..475ef3086 100644
--- a/moto/awslambda/models.py
+++ b/moto/awslambda/models.py
@@ -305,7 +305,7 @@ class LambdaFunction(CloudFormationModel, DockerModel):
             elif key == "Timeout":
                 self.timeout = value
             elif key == "VpcConfig":
-                self.vpc_config = value
+                self._vpc_config = value
             elif key == "Environment":
                 self.environment_vars = value["Variables"]
 
diff --git a/tests/test_awslambda/test_lambda.py b/tests/test_awslambda/test_lambda.py
index 7e4fc22f5..8308195fb 100644
--- a/tests/test_awslambda/test_lambda.py
+++ b/tests/test_awslambda/test_lambda.py
@@ -1536,6 +1536,7 @@ def test_update_configuration():
         Handler="lambda_function.new_lambda_handler",
         Runtime="python3.6",
         Timeout=7,
+        VpcConfig={"SecurityGroupIds": ["sg-123abc"], "SubnetIds": ["subnet-123abc"]},
         Environment={"Variables": {"test_environment": "test_value"}},
     )
 
@@ -1548,6 +1549,11 @@ def test_update_configuration():
     assert updated_config["Environment"]["Variables"] == {
         "test_environment": "test_value"
     }
+    assert updated_config["VpcConfig"] == {
+        "SecurityGroupIds": ["sg-123abc"],
+        "SubnetIds": ["subnet-123abc"],
+        "VpcId": "vpc-123abc",
+    }
 
 
 @mock_lambda