This article explores the role of the military in perpetuating authoritarianism in the Muslim world. Using cross-national data, the article demonstrates that military repression of large-scale protests has been more likely in Muslim-majority states than elsewhere. It offers three explanations for violent military responses to protests: chronic insecurity and political violence, exceptionally high levels of foreign military assistance, and military organizational cultures that favor authoritarian responses to unrest. The article finds no support for claims that Islam as a culture or religion has any systematic effect on military behavior. Several cases of successful democratization in the region demonstrate that authoritarianism is not an immutable feature of Muslim-majority societies.