Abstract: Asking people a question about performing a target behavior influences future performance of that behavior. While contextually robust and methodologically simple, this “question–behavior effect” reveals theoretical complexity as evidenced by the large number of proposed explanations for the effect. Furthermore, considerable heterogeneity exists regarding the “question” used to elicit the effect and the variety of different types of target “behaviors” for which the effect has manifested. A meta‐analytic synthesis of 104 question‐behavior studies across 51 published and unpublished papers is presented. Grouping proposed theories for the effect into four overarching categories, we derive and test systematic predictions regarding potential moderators of conceptual and practical significance. Our findings provide varying degrees of support for four different theoretical mechanisms (attitudes, consistency, fluency and motivations) proposed to underlie the effect. Insights into these mechanisms are presented and outstanding gaps in our understanding are identified as opportunities for future research.