This study aimed to systematically review existing randomized clinical trials on the effect of dietary interventions on endometriosis. A search was performed on the Cochrane Central Register of Controlled Trials (CENTRAL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Clinical Trials, EMBASE, PubMed, Lilacs, and Cielo databases. The search terms were used: "endometriosis", "endometrioma", "diet", "supplements" and "nutrition". Electronic literature searches through databases yielded 866 publications. Two authors performed The study selection independently (and blinded), and disagreements were discussed. Eleven RCTs were included in the systematic review, with 716 women randomized. Most studies reported a positive effect on endometriosis pain scores; however, they were characterized by moderate or high-risk bias. Of these, six RCTs, including 457 women with endometriosis, were included in the meta-analysis. Compared with Placebo, antioxidant use was associated with a reduction in dysmenorrhea (mean difference - 1.95 [CI 95%, -3.78 to -0.13]. Supplementation was not significant for reducing chronic pelvic pain (mean difference - 2.22 [95% CI, -4.99 to 0.55] and dyspareunia (MD - 2.56 [95% CI, - 5. 22 to 0.10]. Both analyses showed a high degree of heterogeneity. Moreover, studies with low risk of bias did not show significant results compared to those on Placebo. The effects of nutrient compounds seem to have the potential to reduce pain in women with endometriosis, mainly to reduce dysmenorrhea. However, the available studies present high heterogeneity and moderate/high risk of bias. More randomized clinical trials are needed to accurately determine dietary interventions' short- and long-term efficacy and safety in managing endometriosis pain.