Endometriosis can be defined as the presence of the endometrium outside the uterine cavity. It affects approximately 10% of women of reproductive age and causes infertility, chronic pain, and deterioration of the quality of life. Since the identification of the disease, various pathogenetic mechanisms have been proposed, such as retrograde menstruation, coelomic metaplasia, hormonal imbalance, stem cell involvement, and alterations in epigenetic regulation. However, the underlying pathogenesis of endometriosis remains inadequately understood. Elucidation of the precise mechanism of the development and progression of endometriosis is crucial for effective treatment. This review presents the major pathogenetic theories of endometriosis based on current research studies with a major focus on the potential role of uterine factors.