Objective:To identify trajectories of peer relationships in very preterm and term-born individuals from 6 to 26 years of age and test early-life predictors of these trajectories.Method:As part of the Bavarian Longitudinal Study, 218 very preterm/very low birth weight (VP/VLBW; <32 weeks' gestation/<1500 grams) and 220 healthy term-born (37-42 weeks' gestation) individuals were followed prospectively from birth to adulthood. Parent and self-reports at 6, 8, 13, and 26 years were combined into comprehensive developmentally appropriate scores across 3 domains: peer acceptance, friendships, and peer problems. Latent profile analyses were used to identify trajectories across these 3 domains. Binary and multinomial logistic regressions were used to test the following potential predictors of trajectories: VP/VLBW status, sex, socioeconomic status, neonatal medical risk, parent-infant relationship at 5 months, child inhibitory control at 20 months, and child cognitive abilities at 20 months.Results:Three trajectories were identified for peer acceptance and friendships, and 2 trajectories were identified for peer problems. Higher cognitive abilities predicted more optimal trajectories in peer acceptance (odds ratio: 1.03 [95% confidence interval = 1.01-1.05]), friendships (1.03 [1.00-1.05]), and peer problems (1.06 [1.04-1.09]). In addition, good parent-infant relationships predicted lower peer problem trajectories (1.61 [1.03-2.50]).Conclusion:Early cognitive deficits may underlie persistent peer relationship difficulties in VP/VLBW samples. Positive parent-infant relationships may help reduce preterm children's risk for long-term peer problems.