Disclosed are compositions and methods including Anti-Müllerian Hormone (AMH) receptor binding peptides. The AMH receptor binding peptides can be used, for example, to modify the activity of the AMH receptor. For example, the AMH receptor binding peptides can activate the AMH receptor, such as the AMH receptor 2, thereby mimicking the function of AMH. In other examples, the AMH receptor binding peptides function as AMH receptor antagonists, thereby interfering with the function of endogenous AMH. By modifying the activity of the AMH receptor, the peptides have multiple applications, including for example modification of treatment of precocious puberty in females, delay of natural menopause, preservation of ovarian follicular reserve, contraception, fertility preservation after ovarian cortex transplant, treatment of endometriosis, treatment of cancer and/or cancer prevention, and treatment of polycystic ovary syndrome (PCOS).