Robert Jefferson is Rowley's father. Mr. Jefferson is a lot more shrill than Mr. Heffley. He won't let Greg or Rowley play any violent video games, and in Book 1 and didn't believe them about their haunted house. In Book 2 Mr. Jefferson didn't look too happy when Greg told Rowley's grandfather that he could have a chocolate cake at his birthday party the next year if he was alive by then. Mr. Jefferson was not pleased when Greg told Rowley that Mr. Jefferson smelled like a woman in a secret language (the secret is: Your-pa dad-pa smells-pa like-pa a woman-pa) at Rowley's sleepover during dinner. Mr. Jefferson ended up sending Greg home before dessert. In Dog Days, he had to bring Greg on their family vacation when their families met at the grocery store. Also in Dog Days, it was shown that Mr. Jefferson had a close bond with Rowley when Greg wrote "Me and Dad might not have one of those close father-son relationships, but that's fine by me. I've learned there's such a thing as TOO close." He shows little interest in sports until in Dog Days, where he is found playing tennis with Rowley and golf with a caddy.