Three grade cohorts of 1,517 public school boys from the 1st, 7th, and 10th grades were drawn from the Pittsburgh Youth Study and were followed over a 4-year period. Correspondence analyses suggested adolescent boys with tolerant attitudes toward theft or violence were more deviant than those who actually committed theft or violent offenses. Stronger attitude effects on subsequent behavior, relative to behavior effects on subsequent attitudes, were found among boys between 10 and 12 years of age. While mean scores of tolerant attitudes toward theft or violence increased linearly with their behavior counterparts between 6 and 17 years of age, ages 11 and 14 were two turning points at which most delinquent attitudes and behaviors escalated at a higher rate. In general, delinquent attitudes and behaviors were related to each other in various patterns, and age was a defining factor that explained many of the inconsistencies in research findings. An appendix provides additional data on the content of attitudes and behaviors. 63 references, 3 tables, and 8 figures