Peer pressure comprises a set of group dynamics whereby a group in which one feels comfortable may override personal habits, individual moral inhibitions or idiosyncratic desires to impose a group norm of attitudess and/or behaviors.

Popular usage associates the term peer pressure particularly with young people or teenagers. The concept can provide an easy, superficial explanation of what occurs when people "go off the rails" or "get in with a bad crowd". But the term can explain much more in the realms of the drive for social acceptance, the spread of fashion and the operations of crowd behavior.