Background: Endometriosis is a chronic, estrogen-dependent inflammatory disorder. It is associated with hormonal dysregulation, pelvic pain, and a reduced quality of life. Dietary factors may influence disease development and symptom severity. Objective: This article aims to summarize current evidence on the role of dietary fiber in endometriosis and to discuss the underlying biological mechanisms and clinical implications. Methods: A narrative review of the literature was conducted using peer-reviewed original research articles and review papers published in English. Studies examining dietary fiber intake, fiber-rich dietary patterns, and their associations with endometriosis risk, symptoms, estrogen metabolism, gut microbiota, and inflammation. Results: Observational studies suggest that higher dietary fiber intake, particularly from fruits, vegetables, and whole grains, may be associated with a reduced risk of endometriosis. Interventional evidence remains limited. However, available studies indicate that fiber-rich dietary patterns may contribute to pain reduction and improvements in quality of life. Conclusions: Current evidence suggests that dietary fiber may play a supportive role in the prevention and management of endometriosis through multiple interconnected biological pathways. Nevertheless, the limited number of high-quality interventional studies highlights the need for further well-designed clinical trials to clarify the therapeutic potential of fiber-rich diets as an adjunct to standard endometriosis care.