Past research suggests that religion imbues people with a sense of certainty - via an increase in personal control, by providing meaning in life, or by activating associated norms. Based on findings suggesting that uncertainty and cognitive dissonance share many underlying features, we investigated whether thinking about religion, either situationally or chronically, buffers against cognitive dissonance. In four methodically diverse studies, we found converging support for this hypothesis. Semantically or symbolically activating Christian religious concepts, as well as being a self-reported believer, attenuated participants' need to reduce post-decisional dissonance via a spreading of alternatives in a free-choice paradigm (Studies 1, 2, & 4) as well as after counterattitudinal advocacy in an induced compliance paradigm (Study 3). The attenuation of post-decisional dissonance was found for a US American online sample (Studies 1 & 4) and for German university students in a laboratory setting, where the dissonance-inducing decision had factual consequences (Study 2).