Although the concept of treatment motivation is generally regarded as highly relevant, it has since long been surrounded by conceptual confusion, resulting in miscommunication, ambiguous measures, and contradictory conclusions of research. This article provides an analysis of three major sources of confusion in the conceptualization of treatment motivation: (a) negligence of the concepts' intrinsic relationship with behavior, (b) entanglement of the concept with its determining factors and behavioral consequences, and (c) conceptualization in a stage model. Following the conceptual analysis, causes of the problems and implications for clinical praxis and research are considered. Finally, a more adequate conceptualization of treatment motivation is proposed and suggestions for future research are made.