In the light of the precursor of sex hormones, dietary fat may affect their levels. In the present meta-analysis, we sought to compare the effects of low-fat versus high-fat diets on sex hormones and their metabolites in adults. Databases were searched up to June 2024 to identify randomized controlled trials comparing low-fat diets (fat intake ≤30% of total energy) with high-fat diets in relation to circulating sex hormone levels. A random-effects meta-analysis was performed, incorporating data from 11 trials with 888 participants. Studies were selected based on their comparison of low-fat versus high-fat diets and the measurement of sex hormone concentrations. The meta-analysis found no significant differences in serum levels of various sex hormones between low-fat and high-fat diet groups. The hormones assessed included estradiol (95% CI, -7.71, 1.10), estrone (95% CI, -12.39, 24.76), sex hormone-binding globulin (95% CI, -3.22, 0.70), dehydroepiandrosterone (95% CI, -0.38, 0.46), testosterone (95% CI, -14.48, 13.50), progesterone (95% CI, -2.82, 1.75), and androstenedione (95% CI, -0.54, 0.03). We found no significant effect of low-fat diets on sex hormones compared with high-fat diets. Our findings, however, were tempered by the small number of studies and low certainty of evidence.