Even when controlling for high levels of delinquent peers, gang youth differ from their nongang counterparts on a variety of attitudinal and behavioral measures. Researchers have argued that differences can be attributed to the group processes present in the gang setting. This study explores the extent to which differences between youth in a gang and those in a delinquent group can be explained by Bandura’s social cognitive theory. Much of the prior research in this arena has relied on cross-sectional data; in this study, we expand on this prior research using fixed-effects modeling strategies with a multi-site panel of youth. The results comparing time periods when youth were in a gang versus a delinquent peer group indicate that gang-involved youth are more violent and have fewer conventional bonds. This work is able to advance our knowledge on attitudinal and behavioral differences between gangs and other types of peer groups.