Attention deficit hyperactivity disorder (ADHD) predicts poor peer relationships. What remains unclear is whether poor peer relationships affect ADHD symptomatology. Hence, reciprocal effects of peer rejection and ADHD symptoms were examined in a community sample of 962 Norwegian children at ages 4, 6, and 8. Results showed that ADHD symptoms at age 4 predicted more peer rejection at age 6, and that peer rejection at age 4 predicted more symptoms at age 6. However, when conducting analyses on ADHD subtypes, hyperactivity-impulsivity and inattentiveness symptoms were adversely affected by peer rejection at ages 6 and 8, whereas peer rejection was unaffected by such symptoms, indicating that the effect of peer rejection on ADHD symptoms was most robust. Mediational relation were also identified.