Decades of research has assessed the benefits of children's and adolescents' friendships, but friendships among youth often dissolve within a matter of months or years. Studies have investigated predictors and consequences of friendship stability with the expectation that, in order for friendships to have a positive or negative influence on youth, they need to be enduring. However, differing methodology used to assess friendships affects the proportion of stable friendships observed, which may confound conclusions. In this meta-analysis a number of methodological and substantive study comparisons were made to assess their contribution to differences in effect sizes across studies of friendship stability. Evaluation of the impact of methodological moderators can inform whether there are differences in methodology that can significantly bias effect sizes of friendship stability. Results suggest that time lag between measurement occasions and presence or absence of a school-year transition impacts friendship stability. However, despite differences in methodology, most differences investigated did not significantly impact friendship stability. This supports the validity of the conclusions drawn from literature on friendship stability.