"Petarded" is the sixth episode of the fourth season of the American animated television series Family Guy. It originally aired on Fox in the United States on June 19, 2005. It was written by Alec Sulkin and Wellesley Wild and directed by Seth Kearsley. In the episode Peter takes the MacArthur Fellows Program test to see if he is a genius. However, he performs so poorly that he is declared technically mentally retarded. Attempting to take advantage of the situation, he accidentally hospitalizes Lois while attempting to steal from a restaurant and loses custody of Meg, Chris, and Stewie.

The episode's title is a double entendre, being both portmanteau between "Peter" and "Retarded" and also a reference to the Shakespeare-coined phrase "hoist with his own petard". This title practice would later be used on a few more episodes, namely "Peterotica" and "Petergeist".

"Timer", a character from 1970s Saturday morning public service announcements, made an appearance in the episode. Series producers tried to get Lennie Weinrib, the actor who had voiced him in the original cartoon segments, to make a guest appearance in the episode. However, Weinrib declined reprising the role as he could not accurately recall the character. "Petarded" gained a Nielsen rating of 4.4, making it the week's 42nd most-watched program. Critics and news sources responded with high praise and many regard this episode as Family Guy's best. Various scenes in the episode were removed by broadcast censors, including one musical number ("Peter is Slow"). It features the guest performances of LeVar Burton, Gary Cole, Barclay DeVeau, Indigo, Phil LaMarr, Cloris Leachman, Len Maxwell, Natasha Melnick, Nicole Sullivan, and Lisa Wilhoit, as well as several recurring voice actors for the series.