Off-time pubertal maturation is associated with mental disorders, presumably due to stress caused by deviation from peers that could also attract negative attention and result in being bullied. Stress related to off-time maturation could be acted out by involving oneself in bullying behavior. The associations between pubertal timing and involvement in bullying have so far not been a focus of research. The objective is to explore associations between off-time pubertal maturation and involvement in bullying. Cross-sectional and longitudinal associations between self-reported pubertal timing and involvement in bullying as victims and perpetrators were studied in a sample of 2070 Finnish adolescents aged 15–17 who participated in the Adolescent Mental Health Cohort Study. Internalizing (depression) and externalizing (conduct disorder) symptoms were controlled for. The adolescents were recruited to response the baseline survey in 2002–2003 (T1) and follow-up two years later (T2). In T1, response rate was 94.4% of all eligible students. The 2070 participants in T2 comprised 63.1% of the T1 participants. Early maturation among boys was cross-sectionally associated with being a bully, and late maturation with exclusion from peer group. After two years, the associations had disappeared. Among girls, no associations were detected between pubertal timing and involvement in bullying. Off-time pubertal maturation places boys at risk for involvement in bullying. The influence is transient and supports the stressful change hypothesis of pubertal timing.