diff --git a/ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java b/ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java
index e313518def..4281cef3f4 100644
--- a/ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java
+++ b/ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java
@@ -93,7 +93,7 @@ public class RubyMessage extends RubyObject {
                         maps.put(fieldDescriptor, map);
                     } else if (fieldDescriptor.isRepeated()) {
                         if (!(value instanceof RubyArray))
-                            throw runtime.newTypeError("Expected array as initializer var for repeated field.");
+                            throw runtime.newArgumentError("Expected array as initializer var for repeated field.");
                         RubyRepeatedField repeatedField = rubyToRepeatedField(context, fieldDescriptor, value);
                         addRepeatedField(fieldDescriptor, repeatedField);
                     } else {