| Number of studies (k): 19 | Effect size: Correlations | ABSTRACT: Why are some people more skilled in complex domains than other people? Here, we conducted a meta-analysis to evaluate the relationship between cognitive ability and skill in chess. Chess skill correlated positively and significantly with fluid reasoning (Gf) (r = 0.24), comprehension-knowledge (Gc) (r = 0.22), short-term memory (Gsm) (r = 0.25), and processing speed (Gs) (r = 0.24); the meta-analytic average of the correlations was (r = 0.24). Moreover, the correlation between Gf and chess skill was moderated by age (r = 0.32 for youth samples vs. r = 0.11 for adult samples), and skill level (r = 0.32 for unranked samples vs. r = 0.14 for ranked samples). Interestingly, chess skill correlated more strongly with numerical ability (r = 0.35) than with verbal ability (r = 0.19) or visuospatial ability (r = 0.13). The results suggest that cognitive ability contributes meaningfully to individual differences in chess skill, particularly in young chess players and/or at lower levels of skill.