Rowley's grandfather

Rowley's Grandfather is the father of Robert Jefferson, father-in-law of Mrs. Jefferson and the grandfather of Rowley Jefferson. So far, he has only made an appearance in Rodrick Rules, and has made no further appearance. He has only been seen in the series when celebrating his birthday, in which Greg mocked him over what birthday cake he would prefer next year. Like Rowley's parents, he dislikes Greg, but this grudge is justified not because of his bad influence on Rowley; it is instead influenced on how Greg mocked him during his birthday.