Don't Mess with Bill is a 1980 Canadian short documentary film about Canadian martial arts pioneer Bill Underwood. At eighty-four, Underwood is a specialist in his own brand of self defense, which he still teaches to police, students, and senior citizens. It was nominated for an Academy Award for Best Documentary Short.
| Production | Pen Densham | Producer |
| Production | John Watson | Producer |
| Crew | Robert C. New | Cinematography |
| Production | Jonathan Watson | Producer |
| Directing | Pen Densham | Director |