This study examined the role of ego development, as measured with the Washington University sentence completion test, in the relationship between pubertal maturation and psychosocial adjustment (self-image and depression) in adolescent boys. The data consisted of 73 boys between 14 and 16 years of age. The results indicated that late maturing boys were also psychologically more immature, and that they experienced negative feelings about sexuality. Additionally, higher ego development was associated with elevated levels of anxiety and depression among late maturing boys. In boys with average pubertal maturation, higher ego development was associated with lower levels of anxiety and depression. (Contains 1 figure and 1 table.)