diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 57e2605edce..590e925a142 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -813,11 +813,13 @@ public class DefaultCodegen implements CodegenConfig {
                             schemas.put(opId, requestSchema);
                         }
                         // process all response bodies
-                        for (Map.Entry<String, ApiResponse> ar : op.getValue().getResponses().entrySet()) {
-                            ApiResponse a = ModelUtils.getReferencedApiResponse(openAPI, ar.getValue());
-                            Schema responseSchema = ModelUtils.getSchemaFromResponse(a);
-                            if (responseSchema != null) {
-                                schemas.put(opId + ar.getKey(), responseSchema);
+                        if (op.getValue().getResponses() != null) {
+                            for (Map.Entry<String, ApiResponse> ar : op.getValue().getResponses().entrySet()) {
+                                ApiResponse a = ModelUtils.getReferencedApiResponse(openAPI, ar.getValue());
+                                Schema responseSchema = ModelUtils.getSchemaFromResponse(a);
+                                if (responseSchema != null) {
+                                    schemas.put(opId + ar.getKey(), responseSchema);
+                                }
                             }
                         }
                     }