We tested the self-perception explanation of the foot-in-the-door effect by manipulating self-perceived helpfulness and assessing self-concept. Participants given $1 to sign a homelessness petition were less likely to see themselves as altruistic than participants not given the monetary incentive. The paid participants also complied less often with a request to work on a canned food drive 2 days later than unpaid participants. In contrast, participants told they were helpful individuals were more likely to see themselves as altruistic and were more likely to volunteer for the food drive than unlabeled participants. Mediation analyses provide evidence that changes in self-concept underlie a successful foot-in-the-door manipulation and support the self-perception explanation for the foot-in-the-door effect.