It is still controversial that GnRH agonist (GnRHa) protects ovarian function from chemotherapy-induced gonadotoxicity. Indeed, the results of many studies related to this issue are neither consistent nor convincing because of the weak study design and the inadequate sample size. We identified 11 prospective controlled studies (8 nonrandomized and 3 randomized) for the systemic review and meta-analysis. The meta-analysis showed that GnRHa cotreatment during chemotherapy can protect ovarian function. However, it is worthy to note that the result of this meta-analysis is influenced by nonrandomized studies. The protective effect of GnRHa will remain elusive until the currently ongoing large, prospective, randomized studies are completed. In addition, tamoxifen, a selective estrogen receptor modulator, may have the protective effect against loss of follicles and ovarian function, which was caused by chemotherapy.