Background: Endometriosis is associated with a wide range of physical symptoms. However, sexual health remains an underrepresented aspect of the disease. Although psychological burden in endometriosis is well documented, mechanisms underlying the maintenance of sexual dysfunction remain insufficiently understood. In particular, the role of metacognitive beliefs has not been systematically investigated. Objective: This study aimed to investigate whether metacognitive beliefs are associated with sexual dysfunction in women with endometriosis and to explore their potential role as a psychological mechanism contributing to symptom maintenance. Design: The survey was conducted at a tertiary endometriosis center. Women with endometriosis confirmed by gynecological examination and transvaginal ultrasound were eligible to participate (n = 316). Data were collected using questionnaires assessing metacognitive beliefs (MCQ), sexual functioning (FSFI) and mental health (PHQ). Descriptive and inferential statistical methods were used for analyzing the data. Results: Sexual problems were found in 64,1% (n=166), especially the capacity to feel desire was impaired in 68,2% (n=152). Comparing women with low and strong metacognitive thoughts, there are relevant differences: endometriosis patients with strong metacognitive beliefs are impaired in arousal (p=0,004), have less lubrication (p=0,005), feel less satisfaction (p=0,010) and have a reduced capacity in achieving orgasm (p=0,012). Endometriosis affects in particular subcategories of metacognitive thoughts “positive worry beliefs” and “cognitive confidence”. Conclusion: Dyspareunia and sexual impairment are common in women with endometriosis, even if it may not be directly reported. Our findings suggest that metacognitive beliefs may represent a relevant psychological factor associated with sexual dysfunction in endometriosis, highlighting the potential value of integrating psychological assessment into clinical care. Physicians may pay more attention to individual mindsets and open up for psychotherapeutic strategies.