In this entry, which is part of the forthcoming Encyclopedia of Private International Law (edited by Jürgen Basedow, Franco Ferrari, Pedro de Miguel Asensio, & Giesela Rühl, Edward Elgar, forthcoming 2017), I explore the doctrine of international comity in private international law and conflicts law. The notion of comity is often employed in public international law where it denotes acts, practices, and rules of goodwill, amity, and courteous treatment habitually observed by nation-states in their interactions with one another. With respect to private international law, or conflict of laws, the issue is far less settled. There, comity is seen as the historical nucleus of private international law doctrine. But beyond this, the nature and functions of comity are unclear. It is particularly comity’s lack of structure, its doctrinal incompleteness, and the dearth of practical guidelines that cause problems.