This paper analyzes relationships between Islamic religious behaviors and civic engagement in Europe and North America. Using data from an original survey of Muslims in Canada, France, Germany, the UK, and the United States, it finds that Muslim religious behaviors relate to civic behaviors in varied ways. The conventional distinction between public and private religious behaviors does not graft perfectly on to Islamic religious behaviors, but the way Islamic religious behaviors straddle the public-private divide help explain their relationships with civic behaviors. Mosque attendance, an example of public religious behavior, is positively associated with secular organizational membership and mainstream political behaviors, and negatively associated with protest activity. Private, or quasi-private, religious behaviors are more commonly associated with protest activities. There are some national-level differences in patterns of civic engagement after controlling for other determinants, but not many, suggesting similar mechanisms mobilize and facilitate Muslim civic incorporation across national contexts. The results suggest that Islamic religious behaviors create diverse opportunities for Muslims to engage as civic citizens.