["Social Development, Volume 35, Issue 3, August 2026. ", "\nABSTRACT\nPuberty is a key developmental process influencing youths’ psychosocial adjustment, yet research has rarely examined its links to adaptive outcomes such as prosocial behavior. Using data from the Avon Longitudinal Study of Parents and Children, we applied linear mixed‐effects models to test associations between pubertal timing and tempo—derived from SITAR growth curve modeling of up to nine assessments (ages 8–17 years)—and mother‐reported behavioral adjustment at age 16 years. Pubertal data were available for 5013 girls and 4822 boys. Pre‐registered analyses showed no associations between puberty and either prosocial behavior or externalizing problems at age 16. Exploratory analyses revealed that earlier pubertal timing and faster tempo were linked to more internalizing problems at age 16. At age 13, earlier timing predicted more externalizing problems, whereas later timing predicted more prosocial behavior. Most of these associations were attenuated in moderation analyses examining interactions between pubertal maturation and either parent–child disclosure or friendship satisfaction. Findings highlight developmental specificity in puberty–behavior links and suggest that supportive social relationships may buffer risks of early or rapid pubertal maturation.\n"]