diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java
index 1457d1d2e6f..e68d6c3509c 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java
@@ -195,7 +195,8 @@ public class SinatraServerCodegen extends DefaultCodegen implements CodegenConfi
     public String toModelFilename(String name) {
         // model name cannot use reserved keyword, e.g. return
         if (isReservedWord(name)) {
-            throw new RuntimeException(name + " (reserved word) cannot be used as a model name");
+            LOGGER.warn(name + " (reserved word) cannot be used as model filename. Renamed to " + underscore("model_" + name));
+            name = "model_" + name; // e.g. return => ModelReturn (after camelize)
         }
 
         // underscore the model file name