This book constitutes the refereed proceedings of the 15th International Conference on Simulation of Adaptive Behavior, SAB 2018, held in Frankfurt/Main, Germany, in August 2018.The 21 papers presented were carefully reviewed and selected from 39 submissions. They cover the main areas in animat research, including the animat approach and methodology, perception and motor control, action selection and navigation, learning and adaptation, and collective and social behavior.