One hypothesis has suggested that adolescents who are "off-time" (early or late) in their pubertal development with respect to peers experience more stress, which makes them more vulnerable to adjustment and behavior problems. A second hypothesis posits that being an early developer is disadvantageous, especially for girls, because the opportunity has passed for completion of normal development tasks of middle childhood. The mismatch between physical and psychosocial development means that expectations for mature behavior occasioned by physical appearance are not matched by the psychosocial maturity and skills required to meet those expectations. This research tested these hypotheses by enrolling 52 girls, ages 9- to 14-years-old, and 56 boys, ages 10- to 15-years-old, in a longitudinal study, along with their parents. Parents completed the Child Behavior Checklist, and the adolescents completed the Offer Self-Image Questionnaire. Regression analysis revealed that later maturing boys and girls had more adjustment and behavior problems than on-time or earlier maturers. Longitudinally, there were few significant relationships between pubertal timing at the first occasion of measurement and adjustment and behavior problems 1 year later. Overlap in correlates of adjustment and behavior problems across rater was not always found. More significant findings were found between pubertal timing and adjustment and behavior problems for boys than for girls, along with more for ratings by PE than by SR or PR. These findings suggest that restraint should be practiced when drawing conclusions about pubertal timing and adolescent behavior when rater of pubertal development or timing of rating varies across studies. The selection of who rates pubertal development and the timing of the rating should be based on the underlying theoretical framework that guides the hypotheses. 2 tables and 64 references