This study explored five teacher professional competencies: working achievement, motivation, service mind, self-development, teamwork, and teacher's ethics and integrity. A total of 210 university students in Thailand participated in the study. To assess professional competency, the Teacher Professional competency Assessment was used. Results revealed that teacher professional competency were at high level. Analysis of factors that contributed to this, in comparison with earlier studies, were discussed. An alternative perspective is suggested that considers teachers as adult learners who continuously transform their meaning of structures related to online teaching through a continuous process of critical reflection and action. The study demonstrated that a professional development programme for teachers in Thailand is necessitated, one that is closely adapted to a specific context. It further indicates that future models of professional development should be ones which are capable of offering a means by which the desired change to a learner-centred, communicative curriculum might be achieved systemwide in Thailand, one that has up to this point proved very difficult to implement.