Background: Adverse experiences -- such as abuse and neglect -- occurring during childhood and adolescence have been found to predict poorer mental and cognitive health. Social adversities, including bullying and social exclusion, are likely to be particularly salient during adolescence. However, our understanding of how social adversities co-occur in adolescence and how they predict cognitive functioning is limited. Methods: We used latent profile analysis to investigate adolescents' experiences of social adversities and regressions to identify their relationship to cognition later in development. Data was analysed from UKHLS (N = 493, aged 14-16 years, preregistered analysis) and ALSPAC (N = 14,856, aged 12-22 years, replication analysis). Results: Adolescents clustered into four profiles in both cohorts: low adversity, peer difficulties, sibling bullying and poly-adversity. We found that 17%-22% of participants fell into the poly-adversity profile and reported experiencing several social adversities. In ALSPAC, but not UKHLS, cognitive functioning differed between social adversity profiles (working memory: F(3, 3773) = 8.07, p < 0.001; fluid reasoning: F(3, 5258) = 3.36, p = 0.018; verbal fluency: F(3, 5261) = 6.24, p < 0.001). After controlling for sex, adolescents in the low adversity profile scored significantly higher on the working memory task than those in the sibling bullying profile and the poly-adversity profile, but effect sizes were small. Conclusion: These findings have implications for understanding adolescents' social experiences. To understand individual differences in lifespan outcomes, it is essential to capture a broad spectrum of social interactions, including peer and sibling difficulties, bullying, exclusion, and school issues.