diff --git a/moto/apigateway/models.py b/moto/apigateway/models.py
index 06637205d..1390db1a3 100644
--- a/moto/apigateway/models.py
+++ b/moto/apigateway/models.py
@@ -92,7 +92,7 @@ class Deployment(CloudFormationModel, dict):
     ):
         properties = cloudformation_json["Properties"]
         rest_api_id = properties["RestApiId"]
-        name = properties["StageName"]
+        name = properties.get("StageName")
         desc = properties.get("Description", "")
         backend = apigateway_backends[account_id][region_name]
         return backend.create_deployment(
@@ -220,7 +220,7 @@ class Method(CloudFormationModel, dict):
         resource_id = properties["ResourceId"]
         method_type = properties["HttpMethod"]
         auth_type = properties["AuthorizationType"]
-        key_req = properties["ApiKeyRequired"]
+        key_req = properties.get("ApiKeyRequired")
         backend = apigateway_backends[account_id][region_name]
         m = backend.put_method(
             function_id=rest_api_id,
diff --git a/moto/cloudformation/parsing.py b/moto/cloudformation/parsing.py
index b38aa7e1b..a303b6861 100644
--- a/moto/cloudformation/parsing.py
+++ b/moto/cloudformation/parsing.py
@@ -185,7 +185,11 @@ def clean_json(resource_json, resources_map):
                             {"Ref": re.findall(r'(?<=\${)[^"]*?(?=})', sub)[0]},
                             resources_map,
                         )
-                    fn_sub_value = fn_sub_value.replace(sub, cleaned_ref)
+                    if cleaned_ref is not None:
+                        fn_sub_value = fn_sub_value.replace(sub, cleaned_ref)
+                    else:
+                        # The ref was not found in the template - either it didn't exist, or we couldn't parse it
+                        pass
                 for literal in literals:
                     fn_sub_value = fn_sub_value.replace(
                         literal, literal.replace("!", "")
diff --git a/tests/test_apigateway/test_apigateway_cloudformation.py b/tests/test_apigateway/test_apigateway_cloudformation.py
index d6cdea3ba..b1d72fa39 100644
--- a/tests/test_apigateway/test_apigateway_cloudformation.py
+++ b/tests/test_apigateway/test_apigateway_cloudformation.py
@@ -290,6 +290,28 @@ template = """{
   }
 }"""
 
+template_with_missing_sub = """{
+  "AWSTemplateFormatVersion": "2010-09-09",
+  "Description": "AWS CloudFormation template",
+  "Resources": {
+    "UnknownResource": {"Type": "AWS::Cloud9::EnvironmentEC2", "Properties": {}},
+    "ApiGatewayRestApi": {
+      "Type": "AWS::ApiGateway::RestApi",
+      "Properties": {
+        "Name": "test-api",
+        "Description": {"Fn::Sub": "${UnknownResource}"},
+        "EndpointConfiguration": {
+          "Types": [
+            "EDGE"
+          ]
+        }
+      }
+    }
+  },
+  "Outputs": {
+  }
+}"""
+
 
 @mock_cloudformation
 @mock_lambda
@@ -347,3 +369,15 @@ def test_simple_apigateway_with_lambda_proxy():
     statement["Condition"]["ArnLike"]["AWS:SourceArn"].should.equal(
         "arn:aws:execute-api:us-east-1:123456789012:{}/*/*".format(api_id)
     )
+
+
+@mock_apigateway
+@mock_cloudformation
+def test_apigateway_with_unknown_description():
+    region = "us-east-1"
+    apigw = boto3.client("apigateway", region_name=region)
+    cf = boto3.client("cloudformation", region_name=region)
+    cf.create_stack(StackName="teststack", TemplateBody=template_with_missing_sub)
+
+    api = apigw.get_rest_apis()["items"][0]
+    api.should.have.key("description").equals("${UnknownResource}")