Burgess and Akers (1966) revised basic differential association theory by specifying the processes by which criminal behavior is learned. They created a social learning theory of crime and deviance by adding principles of operant conditioning to differential association theory. Through rewards and punishments that increase and decrease the likelihood of certain behavior, the individual learns to act in certain ways. In the current study, differential association was examined as an explanation for joining a gang. Data used for the analysis were taken from a 2001 study of high school students in a large urban community in Canada. A total of 543 students completed self-administered questionnaires. The survey was administered in schools located in neighborhoods with considerable gang activity. As a measure of gang membership, the study relied upon respondents' perceptions as to whether they were or were not in a gang. A measure of differential association was based on responses to five items that measured whether the person held values that were favorable or unfavorable to law violations. The study found that values favorable to law violations were significantly related to gang membership, thus confirming predictions derived from both differential association theory and social control theory. Also consistent with differential association theory, the study found that peer delinquency was a significant correlate of gang membership. Consistent with previous research, parental attachment was not a significant correlate of gang membership. Suggestions are offered for future research. 3 tables and 21 references