It appears from this analysis that the onset of exposure to delinquent friends typically precedes the onset of one's own illegal behavior. In addition, the analysis indicates that adolescents tend to gradually become more involved with more delinquent friends, and to gradually become more involved in more delinquent behavior, from early to middle adolescence, and then to become less involved in both delinquent peer groups and delinquent behavior as they enter young adulthood. Some association with delinquent peers typically precedes initiation of minor delinquent behavior, but it also appears to be the case that after onset, some illegal behavior precedes involvement in more delinquent peer groups. These patterns are further confirmed in a structural equation model of the relationship among delinquent peer group bonding, a product of the delinquency of one's friends and the amount of time one spends with one's friends; belief that it is wrong to commit illegal acts; and delinquent behavior. The structural equation model indicates that the influence of delinquent peer group bonding on delinquent behavior is consistently stronger than the influence of delinquent behavior on peer group bonding. These results are more consistent with social learning theory than with either control theory or interactional theory. Tables, figures, references