Cognitive theories of obsessive-compulsive disorder (OCD) posit that maladaptive beliefs lead to the development and maintenance of symptoms. However, currently identified beliefs (about responsibility and threat overestimation, perfectionism and intolerance for uncertainty, and about the importance of and control over thoughts) do not sufficiently explain OCD symptomatology. Anecdotal and other reports have documented concerns among those diagnosed with OCD regarding a potential loss of control over their thoughts and behaviour, indicating that negative beliefs about losing control may be an important cognitive domain involved in the aetiology of OCD. In this study, 133 undergraduate participants received (positive or negative) false feedback about their capacity to stay in control during a bogus EEG session, and completed a computer task asking them to control the pace of a series of pictures. As hypothesized, participants provided with negative feedback about their capacity to stay in control (i.e., high negative beliefs about losing control) checked significantly more often which keys they should use to control the pictures, t(106.95) = 2.28, p = .02, d = .44, as compared to participants provided with positive feedback (i.e., low negative beliefs about losing control), demonstrating that manipulating beliefs about losing control can impact checking behaviour. Also, checking behaviour predicted a lower desire for control over the computer task’s pictures, r(131) = -.30, p < .001, such that compulsions may be seen as opportunities to re-establish disrupted perceptions of control. Results support the inclusion of beliefs about losing control in cognitive models of OCD.