The current study adopted meta-analysis method to determine the effect of school readiness programs on preschool children. The researchers scanned national (i.e., Turkish) and international databases for studies conducted using experimental and quasi-experimental methods which were published between 2008 and 2022 that met this study's inclusion criterion. The search yielded 3254 studies on school readiness, of which 258 adopted experimental or quasi-experimental designs. However, 16 studies (N = 3254) meeting the inclusion criteria were evaluated within the scope of this study. The school readiness intervention programs were found to be positive and significant, and using the standard set forth by Cohen (1992), the results yielded a large effect size (g = 0.932). The results highlighted significant differences in groups in terms of age and duration of the intervention variables. The overall results will shed a light in designing effective school readiness intervention programs.