Russian and Turkish interests have clashed over Syria since the beginning of the conflict in late 2011. Yet, in Summer 2016, the two governments emerged as deal makers in the Syrian conflict. Due to a host of international and regional reasons, Russia and Turkey have enhanced cooperation on the ground in Syria. This article argues that the concept of alignment best captures the various forms of security cooperation taking shape in different regions of the world and is useful to explain Russian-Turkish security cooperation in Syria. It offers a detailed account of the origins and key components of Russian-Turkish geopolitical alignment in Syria. Military coordination and the search for a political settlement have been the salient components of this process. Cooperation in Syria has also had a spillover effect in other sectors. However, the article argues that Russian-Turkish geopolitical alignment is unlikely to transform into a more durable security partnership as the two countries continue to prefer divergent outcomes in Syria. Still, Russian-Turkish geopolitical alignment has significant implications for the regional order in an age of American decline.