People in power positions should be able to control their impulses and act in line with long-term goals. However, two influential theories disagree as to whether power is conducive or detrimental to exercising self-control. We propose to resolve this contradiction by distinguishing between initiatory (“start”) and inhibitory (“stop”) self-control components that may be differentially affected by social power. Ninety-five female participants were randomly assigned to either a powerful role (interviewer) or a powerless role (applicant) and interacted in a simulated job interview (i.e. a modified Trier Social Stress Test). They then completed two inhibitory (d2 Test of Attention and emotion regulation) and two initiatory (handgrip and creative problem-solving) self-control tasks. We tested the hypotheses that social power benefits task performance if the task requires start self-control but impairs task performance if the task requires stop self-control. Although the power manipulation strongly affected participants’ sense of power, it did not significantly affect self-control performance. Considering that this preregistered study had 80% power to detect an effect of d = 0.64, we conclude that the population effect size is smaller than that.