This chapter reviews the literature on compliance, a type of social influence that occurs when a person changes their behavior in response to a direct request. Specifically, I review research on compliance organized by the six classic principles of social influence (Cialdini, 2009)—reciprocity, commitment and consistency, authority, social validation or social proof, and liking and similarity, and examine how they are used to change peoples’ behaviors. Furthermore, this chapter reviews the mechanisms that underlie these principles, particularly mindlessness. Finally, this chapter concludes by examining whether this framework for understanding compliance applies to the new realm of social influence—social media—and calls for more research on the effectiveness of the principles of influence when the mode of interpersonal interaction is software based rather than in person.