This article traces how Ottoman interpretations and uses of Islamic law adapted to deal with non-Muslim rebellions between roughly 1769 and 1830. Drawing on Ottoman fatwas (legal opinions), bureaucratic registers, sultanic decrees, and chronicles, as well as British diplomatic records, it argues that the Ottoman state actively reinterpreted its commitment to the Islamic legal tradition in order to forge the law of rebellion into a weapon against both foreign and domestic enemies. The Ottomans first used declarations of rebellion to mobilize military forces against its imperial rivals, then to discourage and suppress domestic dissent, and finally to deny rebels’ sovereignty under international law. In doing so, the Sublime Porte effectively redefined sovereignty by interleaving Islamic and international concepts. The article places this development in global context, arguing that it resembled legal moves made by Atlantic states as they dealt with the Age of Revolutions. At the same time, this story shows how the Ottoman state’s commitment to Islamic law, and its employment of officially authorized scholars to interpret that law, could both license and constrain state policy. The Islamic legal tradition was flexible, but also meaningful. Interpretation occurred at different levels, and was done by different actors. While the state had significant latitude, it faced limits arising from the substance of the law and the process of interpretation itself.