How can people persuade and influence others? One option is to directly target others' behavior through rules and incentives. Another increasingly popular option, however, is to focus on modifying what others think rather than how they behave, and hoping behaviors will then change as a result. The assumption underlying this latter approach is that targeting thoughts and attitudes might be easier or more effective than targeting behaviors. Drawing from psychological reactance theory (Brehm, 1966), we investigate whether efforts targeted at controlling what people think, rather than how they behave, will indeed be met with differing levels of psychological reactance. Across four studies, we find that people experience greater psychological reactance towards efforts to control their thoughts compared to efforts to control their behaviors. Specifically, thought control, compared to behavioral control, led people to experience greater anger and negativity, and to report lowered motivation to engage in requested behaviors (Study 1). These effects occurred, at least in part, because people perceived that those who try to control their thoughts are likely to try to control their behaviors too, but not vice versa. As a result, thought control elicited greater reactance than behavioral control because the former was perceived as more restrictive than the latter (Studies 2 & 3). We also address other explanations for why thought control may elicit more reactance than behavioral control (Study 4).