Theory of Mind research has traditionally emphasized its predictive function (e.g., predicting someone will be angry after being stuck in traffic). Prediction tasks have dominated decades of experimental and computational research.Theory of Mind is also used to plan interventions on other minds (e.g., choosing how to cheer someone up who has been stuck in traffic) and representations used for planning will have different requirements from those only used for prediction.Research on planning emphasizes the importance of abstract and structured causal models, like Theory of Mind.Focusing on Theory of Mind for planning can illuminate a range of socio-cognitive phenomena, such as interpersonal affect regulation, impression management, pragmatic speech, and pedagogy.Understanding Theory of Mind should begin with an analysis of the problems it solves. The traditional answer is that Theory of Mind is used for predicting others’ thoughts and actions. However, the same Theory of Mind is also used for planning to change others’ thoughts and actions. Planning requires that Theory of Mind consists of abstract structured causal representations and supports efficient search and selection from innumerable possible actions. Theory of Mind contrasts with less cognitively demanding alternatives: statistical predictive models of other people’s actions, or model-free reinforcement of actions by their effects on other people. Theory of Mind is likely used to plan novel interventions and predict their effects, for example, in pedagogy, emotion regulation, and impression management.