This paper explores the impact of group affiliation with respect to the on-line processing and appreciation of jokes, using facial electromyography (EMG) activity and offline evaluations as dependent measures. Two experiments were conducted in which group affiliation varied between the participant and each of two independent (recorded confederate) speakers whose described political profiles were distinguished through one word: “Right” versus “Left.” Experiment 1 showed that jokes were more highly evaluated and that associated EMG activity was more intense when it was later determined that the speaker was a member of the listener’s ingroup rather than outgroup. In an effort to determine whether these parochial effects can be isolated to ingroup favoritism as opposed to outgroup derogation, Experiment 2 paired a joke-teller described as politically active (either from the right or the left) with one who was described as politically neutral. These more subtle comparisons suggest that the parochial effects observed in the joke understanding paradigm are mediated, at least in part, by the presence of an outgroup member. Keywords: language processing, parochialism, humor, social laughter