1 Department of Psychology, McGill University, Montreal, Quebec, Canada.
2 Department of Psychology, Concordia University, Montreal, Quebec, Canada.

This meta-analysis examined concurrent associations between aggression, withdrawal, assertion, and prosocial behavior and each of positive and negative friendship quality across studies with 22,657 children and adolescents (M_age = 11.71 years; 51.7% girls; 67.7% White). Studies were published between 1995 to 2021 and 32.4% were conducted outside of North America. Aggression was linked to more negative, $\overline{r}$ = .19, 95% CI [.14, .24], and less positive, $\overline{r}$ = -.05 [-.08, -.01], friendships. Withdrawal was associated with less positive friendships, $\overline{r}$ = -.13 [-.18, -.08], whereas prosocial behavior was related to more positive, $\overline{r}$ = .29 [.22, .37], as well as less negative, $\overline{r}$ = -.16 [-.20, -.12], friendships. Assertion was related to more positive friendships, $\overline{r}$ = .15 [.01, .28].