This article examined associations between indices of maturation (age and Tanner stage) and amygdala volumes in 24 youth (aged 7-14) with posttraumatic stress disorder symptoms and a matched control group. Fifteen of the youth with exposure to trauma were also re-evaluated one year later. A positive association between maturation and right amygdala volumes was observed in the trauma group but not in controls. Associations with maturation remained when controlling for a number of possible covariates and over time. Developmentally younger youth (Tanner stage 1 and 2) showed increases and older (Tanner stage 3 and 4) decreases in right amygdala volumes.