Sexual dysfunctions, particularly sexual pain, are common in adult women of all ages. In patients with endometriosis, a chronic gynecological pain condition affecting women of reproductive age, sexual pain is the third most common symptom. Multiple biological factors are involved in endometriosis-related sexual pain including tissue damage, inflammation, hormonal changes, alterations within the peripheral and central nervous system and pelvic floor muscle dysfunctions. Conceptual models of sexual pain espouse a multifactorial view, with empirical evidence suggesting the implication of psychosexual and relationship difficulties in the development and persistence of sexual pain and associated distress. We review literature on the biological, psychological, sexual and interpersonal factors associated with development and persistence of sexual pain in women with endometriosis. In addition, we discuss chronic pain conditions frequently associated with endometriosis (vulvodynia, bladder pain syndrome and inflammatory bowel syndrome) and how they are linked with sexual pain. Finally we discuss the clinical implications and provided suggestions for future research and medical care, focusing on a multidisciplinary and biopsychosocial approach.