It has been twenty years since Clark and Chalmers published “The Extended Mind.” In the present article I review the development of the extended mind hypothesis across what some proponents have defined as three theoretical “waves.” From first‐wave extended mind theory, based on the parity principle, to second‐wave complementarity, to the third wave, characterized as an uneasy integration of predictive processing and enactivist dynamics, extended mind theorists have faced and solved a number of problems along the way. The fact that the hypothesis continues to spark debate and to generate both new insights and new objections suggests that it continues to play a productive role in contemporary philosophy of mind.