The popularity of social networking sites (SNSs) among adolescents and young adults has raised concerns that the intensity of using these platforms might be associated with lower academic achievement. The empirical findings on this issue, however, are anything but conclusive. Therefore, we present four random-effects meta-analyses including 59 independent samples (total N = 29,337) on the association between patterns of SNS use and grades. The meta-analyses identified small negative effects of ?ˆ= -0.07, 95% CI [-0.12, -0.02] for general SNS use and ?ˆ= -0.10, 95% CI [-0.16, -0.05] for SNS use related to multitasking. General SNS use was unrelated to the time spent studying for school (?ˆ= -0.03, 95% CI [- 0.11, 0.06]) and no support for the time displacement hypothesis could be found in a meta-analytical mediation analysis. SNS use for academic purposes exhibited a small positive association, ?ˆ= 0.08, 95% CI [0.02, 0.14]. Hypotheses with regard to cross-cultural differences were not supported.