Formal school is full of new demands for young children. In this new environment, children need to pay attention for longer periods, acquire knowledge and skills, and inhibit impulsive responses. Does this massive training program improve domain-general cognitive abilities over and above age-related maturation? Prior work leverages a “natural experiment” made possible by the arbitrary school cut-off date for school entry that allows researchers to compare outcome measures from approximately same-age children in different grade levels. An effect of schooling is reported when children in a higher grade show better performance than age-matched peers in a lower grade. To date, there is mixed evidence for this so-called schooling effect on executive functions. Here, we aimed to quantitatively synthesize existing work using meta-analytic methods to determine the size of the executive function schooling effect and compare it to the effect of maturation. We identified 13 studies published between 1995 and 2023 (N = 1706 children, age 3 - 9 years, approximately 51% female), containing a total of 27 effect sizes: nine using working memory measures, four using cognitive flexibility measures, six using inhibitory control measures, and the remaining eight employing global executive function measures. Overall, we found a small-to-moderate schooling effect combining all 27 effect sizes (g = 0.32, 95% CI [0.24, 0.39]). To contextualize this result, we calculated both a maturation and a schooling effect for a subset of studies (13 effect sizes, n = 485) where this calculation could be standardized (i.e., those using a longitudinal cutoff design). For this subset of effect sizes, the maturation effect (g = 0.37, 95% CI [0.24, 0.50]) was larger than the schooling effect (g = 0.26, 95% CI [0.13, 0.39]). Our results show that spending one year in school, this massive and ubiquitous experience has some, but not an exceptionally large effect on children’s domain-general cognition.