This review discusses the role of hormones in testicular development and function, emphasizing their importance in male fertility. The testes produce sperm and male sex hormones, with hormones regulating testicular development and function throughout life. Key hormones include testosterone, follicle-stimulating hormone (FSH), inhibin B, activin A, anti-Müllerian hormone (AMH), insulin-like factor 3 (INSL3), and estrogen. These hormones are regulated by the hypothalamic–pituitary–gonadal (HPG) axis, which is active at different life stages. Hormonal imbalances can lead to reproductive disorders, and understanding these hormonal interactions is crucial for developing new therapeutic methods and male hormonal contraceptives. The HPG axis plays a critical role in male reproduction, with its activation occurring in three distinct waves during fetal life, minipuberty, and puberty. Disruptions in the HPG axis can affect reproductive health, and male hypogonadism, characterized by low testosterone levels, can result from testicular dysfunction, hypothalamic-pituitary diseases, or obstructive azoospermia. Hormonal contraceptives, such as testosterone undecanoate, are being developed to provide effective and reversible male contraception.This review discusses the role of hormones in testicular development and function, emphasizing their importance in male fertility. The testes produce sperm and male sex hormones, with hormones regulating testicular development and function throughout life. Key hormones include testosterone, follicle-stimulating hormone (FSH), inhibin B, activin A, anti-Müllerian hormone (AMH), insulin-like factor 3 (INSL3), and estrogen. These hormones are regulated by the hypothalamic–pituitary–gonadal (HPG) axis, which is active at different life stages. Hormonal imbalances can lead to reproductive disorders, and understanding these hormonal interactions is crucial for developing new therapeutic methods and male hormonal contraceptives. The HPG axis plays a critical role in male reproduction, with its activation occurring in three distinct waves during fetal life, minipuberty, and puberty. Disruptions in the HPG axis can affect reproductive health, and male hypogonadism, characterized by low testosterone levels, can result from testicular dysfunction, hypothalamic-pituitary diseases, or obstructive azoospermia. Hormonal contraceptives, such as testosterone undecanoate, are being developed to provide effective and reversible male contraception.