Strain theory is different from social control and social learning theory in its specification of the type of social relationship that leads to delinquency and the motivation for delinquency. Strain theory focuses explicitly on negative relationships with others, relationships in which individuals are not treated as they want to be treated. Strain theory also argues that adolescents are pressured into delinquency by negative affective states, most notably anger and related emotions. Three major types of strain theory are described: (1) strain as the actual or anticipated failure to achieve positively valued goals; (2) strain as the actual or anticipated removal of positively valued stimuli; and (3) strain as the actual or anticipated presentation of negative valued stimuli. Guidelines for measuring strain are presented, major adaptations to strain are described, and factors influencing the choice of delinquent versus nondelinquent adaptations are discussed. Strain theory is considered to be the only major theory that focuses explicitly on negative relationships with others and to argue that delinquency results from the negative effects caused by such relationships. As such, it complements social control and differential association/social learning theory in a fundamental way. 162 references