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 be6c725381bf..338b4b91886c 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
@@ -4580,6 +4580,10 @@ public class DefaultCodegen implements CodegenConfig {
         String name = null;
         LOGGER.debug("Request body = " + body);
         Schema schema = ModelUtils.getSchemaFromRequestBody(body);
+        if (schema == null) {
+            throw new RuntimeException("Request body cannot be null. Possible cause: missing schema in body parameter (OAS v2): " + body);
+        }
+
         if (StringUtils.isNotBlank(schema.get$ref())) {
             name = ModelUtils.getSimpleRef(schema.get$ref());
             schema = schemas.get(name);