Purpose In Thailand, Lesbian, Gay, Bisexual, Transgender, and Queer (LGBTQ) individuals face significant health disparities and discrimination in healthcare. A primary cause is the lack of knowledge among doctors and their negative attitudes towards LGBTQ people. The purpose of this study was to explore the current undergraduate medical curricula of medical schools in Thailand concerning learning outcomes, contents, teaching and learning methods, and assessment methods in the field of LGBTQ health. It also sought to gather opinions from principal stakeholders in curriculum development. Methods The authors employed a mixed-methods approach with a convergent design to conduct the research. Quantitative data were collected from 23 deputy deans of educational affairs using a standardized interview form, and qualitative data were obtained through in-depth interviews with key stakeholders including 16 LGBTQ healthcare receivers, 22 medical students, and three medical teachers. Both datasets were analyzed simultaneously to ensure consistency. Results The findings indicate that none of the medical schools had established learning objectives related to LGBTQ healthcare within their curricula. Of the institutions surveyed, 8 out of 15 (53.3%) offered some form of teaching on this topic, aligning with the qualitative data which showed 7 out of 17 institutions (41.2%) provided such education. The most frequently covered topics were gender identity and sexual orientation. Lectures were the predominant teaching method, while multiple-choice questions were the most common assessment format. There was a unanimous agreement among all principal stakeholders on the necessity of integrating LGBTQ healthcare into the M.D. program and the professional standards governed by the Thai Medical Council. Conclusions Although some Thai medical schools have begun to incorporate LGBTQ health into their curricula, the approach does not fully address the actual health issues faced by LGBTQ individuals. Future teaching should emphasize fostering positive attitudes towards LGBTQ people and enhancing communication skills, rather than focusing solely on the cognitive aspects of terminology. Importantly, medical educators should serve as role models in providing competent and compassionate care for LGBTQ patients.