There has been a longstanding interest in criminology and much attention given by criminologists to the relationship between having delinquent friends and delinquent behavior. There has been speculation of theoretical links between differential association and offending. The reason for this speculative linkage is that investigators consistently find that individuals are more likely to offend if they associate with peers who condone and commit crime. Using data from the National Youth Survey (NYS), this study explored the influence of delinquent friends’ behaviors and attitudes on general, group, and solo offending for three crimes. The NYS is a panel study of a national probability sample of persons that were ages 11 to 17 in 1976. The NYS is considered the most complete data set for testing differential association. This analysis was based on 1,492 youths. Both friends’ attitudes and behaviors were significant determinants of three forms of criminal offending: theft, assault, and vandalism. The most important conclusions of the study were that neither own attitudes nor the situational influence of friends appeared to be the mechanism of transference. Group influences were eliminated as the mechanism of differential association. References