Background: The extent of endometriosis is not directly related to the degree of symptoms, and recurrence of symptoms occurs frequently. Given that, an association with psychological distress, as in depression and anxiety disorders, is suggested. Objective: To explore the strength of the associations between endometriosis and depression or anxiety and to review potential correlating factors. Search Strategy: A literature search was carried out using the electronic databases Embase, PubMed, Web-of-science and PsycINFO. Search terms related to depression, anxiety and endometriosis were combined resulting in 1,837 records. Selection criteria: Articles describing an association between endometriosis and depression or anxiety by using validated assessment tools, structured psychiatric interviews or a documented diagnosis were included. Data collection and Analysis: With 47 articles a systematic qualitative review was performed. Seventeen studies were eligible for meta-analysis. Main Results: In the meta-analysis, endometriosis patients experienced significantly more symptoms of depression (SMD of 0.71 (95%CI 0.36, 1.06) and anxiety (SMD 0.60 (95%CI 0.35, 0.84)) compared to healthy controls, but no differences were found comparing endometriosis patients with chronic pelvic pain patients without endometriosis. Besides the effect of pain, other correlating factors included age, quality of life, quality of sleep, fatigue, sexual function, gastrointestinal symptoms, comorbidity, self-esteem, emotional self-efficacy, coping style, social adjustment, pain imagery and pain sensitization. Conclusion: Endometriosis is associated with depression and anxiety. Therefore, an integrated patient-centred approach to medical, psychological and sexual issues is suggested as this may positively influence the perception of symptoms, treatment adherence, quality of life, prognosis and health care costs.