The International Institute of Sociology (IIS) is a scholarly organization which seeks to stimulate and facilitate the development, exchange, and application of scientific knowledge to questions of sociological relevance. Membership is open to all sociologists as well as to scholars in neighbouring disciplines.

Created in Paris in 1893 by René Worms, it is the oldest continuous sociological association in existence. Since its foundation the goal of the IIS has been to bring together sociologists from around the world. It has a longstanding tradition of promoting discussions on the most crucial theoretical issues of the day and on the practical use of social scientific knowledge.

In addition to the congresses and other meetings, the IIS publishes the Annales de l'Institut International de Sociologie / Annals of the International Institute of Sociology. First published in 1895 after the first world congress, this book series is a major forum for the presentation of cutting-edge research and synthesis. The most recent volume After the Soviet Empire: Legacies and Pathways (2015), edited by Sven Eliaeson, Lyudmila Harutyunyan and Larissa Titarenko, is currently available through Brill.