BACKGROUND E-health websites are being increasingly used to obtain information about endometriosis by the community and for self-learning and for recommendations to patients by clinicians. Critical evaluation is needed to inform users of their quality. OBJECTIVE To evaluate the quality of endometriosis e-health websites and provide high-quality recommendations to the community and clinicians. METHODS PRISMA 2020 guidelines informed two Google searches using incognito mode of international and Australian e-health websites. The first search string used terms ‘endometriosis’, ‘adenomyosis’ or ‘pelvic pain’ whereas ‘Australia’ was added to the second search string. Only free e-health websites in English were included. ENLIGHT, a validated tool, assessed the quality of each e-health website across 7 domains. A final average score of >3.7 was considered high-quality. RESULTS Fifty-nine e-health websites were screened and 49 included. Eleven high-quality websites were identified: Endometriosis Australia Facebook Page, Endometriosis UK, National Action Plan for Endometriosis on EndoActive, Endometriosis by Jean Hailes for Women’s Health, Adenomyosis by Jean Hailes for Women’s Health, Endometriosis by IVF Australia, Adenomyosis by Sydney Morning Herald, Endometriosis by National Health System, Endometriosis by Safe Work Australia, Adenomyosis by the Medical Republic, and Endometriosis by Royal Australian College for General Practitioners. These websites provided easily understood, accurate information. The last two e-health websites were resources for clinicians. Recommendations on search engine optimisation are provided to improve reach and discoverability of e-health websites. CONCLUSIONS Although geographical location can influence the search results, we identified eleven high-quality endometriosis e-health websites that can be recommended to those with endometriosis and clinicians. To improve Google ranking, e-health websites should leverage search engine optimisation tools. CLINICALTRIAL A systematic review protocol was developed and registered with the international prospective register of systematic reviews (PROSPERO; registration CRD42020185475) after which the systematic review was conducted according to PRISMA guidelines.