Employing a mixed-methods approach, this project was able to uncover the potential factors affecting the wellbeing of language teachers at the tertiary level in Japan and Vietnam. Using the ecological framework to analyze qualitative data (intensive interviews) from teachers working in Japan and Vietnam, factors pertaining to each layer of the ecosystem of teacher wellbeing were found, providing useful insights for both institutions and educators to protect and enhance language teacher wellbeing when necessary. Quantitative questionnaires were utilized to ascertain those factors as well as provide space for participants to share advice that could help enhance teacher wellbeing. Findings indicate that some factors, such as salary, institutional policies, colleagues, etc., other influencing factors (i.e., autonomy, community of practice, language competency, etc.) characterizing the wellbeing of language teachers in the two studied countries were also found, providing more resources for policy makers. Another significant finding obtained from the project is that it was able to theorize the five stages (i.e., (1) entering the profession; navigating the profession; (3) persevering in the profession, (4) growing in the profession) through which language teachers need to undergo in order to enhance their wellbeing. More importantly, there are specific mentalities that teachers need to be aware of in each stage (e.g., compassion, self-worth, etc.) to protect and enhance their wellbeing. Based on the characteristics of each stage, it is hoped that both language teachers and their institutions can design appropriate training plans to enhance both teachers’ competences and mentality. Finally, findings from the project reveal the similarities as well as the differences between the wellbeing of language teachers in Japan and Vietnam at the tertiary level. For instance, while teachers in Vietnam may have sufficient training during their pre-service program, they were less confident when handling work-related stress. On the other hand, language teachers in Japan have shown a stronger mentality, even though it was a struggle for them to acquire the necessary teaching skills because of a lack of teacher training.