The Iowa Gambling Task (IGT) was designed to assess decision-making under conditions of complexity and uncertainty; it is currently one of the most widely used tests to assess decision-making in both experimental and clinical settings. In the original version of the task, participants are given a loan of play money and four decks of cards and are asked to maximize profits. Although any single card unpredictably yields wins/losses, variations in frequency and size of gains/losses ultimately make two decks more advantageous in the long term. Several studies have previously suggested that there may be a sex-related difference in IGT performance. Thus, the present study aimed to explore and quantify sex differences in IGT performance by pooling the results of 110 studies. The meta-analysis revealed that males tend to perform better than females on the classic 100-trial IGT (UMD = 3.381; p < 0.001). Furthermore, the significant heterogeneity observed suggests high variability in the results obtained by individual studies. Results were not affected by publication bias or other moderators. Factors that may contribute to differences in male and female performance are discussed, such as functional sex-related asymmetries in the ventromedial prefrontal cortex and amygdala, as well as differences in sensitivity to wins/losses.