Objective: To evaluate the efficacy of different hormone therapies in preventing postoperative endometrioma recurrence. Data Sources: The MEDLINE, COCHRANE, and Embase electronic databases were searched from inception to 30 April 2021. Methods of Study Selection: Randomized controlled trials (RCTs) or cohort studies including reproductive age women with endometriosis undergoing ovarian cystectomy or excision of endometriotic lesions compared the effects of postoperative adjuvant therapy (gonadotropin-releasing hormone agonist [GnRHa]) and postoperative maintenance hormone interventions for more than 1 year (i.e., oral contraceptive pills [OCPs], dienogest [DNG], levonorgestrel-releasing intrauterine system [LNGIUS]) on endometrioma recurrence. Tabulation, Integration, and Results: Data collection and analysis of the data were independently performed 2 two reviewers. A total of 11 studies were included, of which 2 were RCTs, and 9 were cohort studies. There were 2394 patients with 6 interventions (cases: 1665, 69.6%) and expectant management (cases: 729, 30.4%). Relative treatment effects were estimated using network meta-analysis and ranked in descending order. The clinical effectiveness of these drugs (vs expectant management) was as follows: GnRHa plus DNG (odds ratio [OR], 0.04; 95% confidence interval [CI], 0.01–0.27), surface under the cumulative ranking (SUCRA) = 94.0; DNG (OR, 0.11; 95% CI, 0.04–0.32), SUCRA = 69.7; GnRHa plus OCP (OR, 0.12; 95% CI, 0.02–0.64), SUCRA = 63.4; GnRHa plus LNGIUS (OR, 0.13; 95% CI, 0.03–0.66), SUCRA = 59.4; and OCP (OR, 0.21; 95% CI, 0.13–0.36), SUCRA = 43.6. The effectiveness of GnRHa (OR, 0.47; 95% CI, 0.12–1.89), SUCRA = 17.3 was not significantly different from that of controls. Conclusion: In network meta-analysis, combined postoperative adjuvant therapy and longer maintenance hormone treatment are better than a single agent in preventing postoperative endometrioma recurrence. GnRHa plus DNG maintenance treatment might be the most effective intervention. Large-scale RCTs of these agents are still required.