Pubertal status and timing were significantly associated with children’s reports of the internalizing symptoms of social anxiety disorder, generalized anxiety disorder, and major depression and with the externalizing symptoms of oppositional defiant disorder, attention deficit disorder, and conduct disorder. Internalizing and externalizing symptoms in pubertal transition were seen in both boys and girls. Both children’s and primary caregivers’ data revealed significant associations between puberty measures and externalizing symptoms. Coming of age too early was found to present a significant risk for the development of emotional and behavioral problems among African-American children. It was suggested that future research target an investigation on the interaction of the pubertal transition with premenarcheal vulnerability factors, neighborhood circumstances, and familial contexts in influencing adjustment among African-American children. Developmental research has long focused on the puberty-behavior link. As a developmental stage, the transition to adolescence exposes youth to a widening array of social and environmental stressors compared to the relatively stress-free childhood. This study was designed to examine the relationship of pubertal maturation with internalizing and externalizing symptoms in a sample of 867 African-American children between the age of 10 and 12. Four questions were addressed in the study: (1) is the pubertal timing associated with internalizing and externalizing behaviors among African-American children as it is among White children; (2) does this relationship vary across gender; (3) does this relationship vary according to the source of information about behavior problems; and (4) are both early and late maturers at higher risk for maladjustment than are on-time maturers? Tables and references