The hypothalamic-pituitary-ovarian (HPO) axis is a tightly regulated system controlling female reproduction. HPO axis dysfunction leading to ovulation disorders can be classified into three categories defined by the World Health Organization (WHO). Group I ovulation disorders involve hypothalamic failure characterized as hypogonadotropic hypogonadism. Group II disorders display a eugonadal state commonly associated with a wide range of endocrinopathies. Finally, group III constitutes hypergonadotropic hypogonadism secondary to depleted ovarian function. Optimal evaluation and management of these disorders is based on a careful analysis tailored to each patient. This article reviews ovulation disorders based on pathophysiologic mechanisms, evaluation principles, and currently available management options.