Mark O’Donnell was an American writer and humorist. O’Donnell and Thomas Meehan shared the 2003 Tony Award for Best Book of a Musical and the Drama Desk Award for Outstanding Book of a Musical for their work on Hairspray, and they wrote the 2007 film adaptation. The pair also worked on another John Waters musical adaptation, Cry-Baby, for which they received a 2008 Tony nomination.
O’Donnell’s novels include Getting Over Homer and Let Nothing You Dismay. Along with Bill Irwin, he wrote Scapin, a 1997 play adapted from the original by Molière.
A 1980 article he wrote for Esquire, "O'Donnell's Laws of Cartoon Motion," was both widely quoted ("1. Any body suspended in space will remain suspended in space until made aware of its situation") and widely circulated by fans of cartoon physics.