Mr. Underwood

Mr. Underwood is Greg's Physical Education teacher. He has a very little role in the first book, teaching the students a wrestling unit. His role in The Last Straw was a minor but important appearance, where he was walking with the principal Mrs. Mancy to mark the students' dancing abilities as 20% of their P.E. grades. In Cabin Fever, he was also shown during a push-up test. In Diary of a Wimpy Kid: The Third Wheel, he is shown being bitten by Ruby Bird.

In the first three films, his counterpart is Coach Malone.