Abstract In this article, we provide a quantitative review of the literature on the effect of cooperative membership on farms productive performance. Based on a dataset composed of 332 estimates from 80 studies, our meta‐regression analysis suggests that the current literature suffers from a severe positive publication bias. After correcting this bias, the overall average effect of cooperative membership on farms' productive performance is positive and statistically significant, but its magnitude is small to negligible. Interestingly, we find that cooperative membership has a stronger effect on yield than on technical efficiency. We also explore how contextual variables and methodological choices affect the reported estimates in the literature.