The China-Iran comprehensive strategic partnership (CSP) has been described as a potentially disruptive alignment. This article analyses the impact of the CSP in two regional security complexes (RSCs): the Persian Gulf and South Asia. It finds that of the two RSCs, the China-Iran CSP has a greater likelihood of affecting the strategic landscape of the South Asian RSC as China seeks to contain India's power and influence. In the Persian Gulf, China's economically-motivated regional presence is supported by the maintenance of the status quo, and as a result the CSP is not likely to adversely affect that RSC.