While previous research has indicated that well-being at work is an important factor influencing the long-term effectiveness of organizations (Diener et al., 2003), limited research in Thailand has explored this relationship, particularly within higher education. Therefore, this study aims to investigate the level of well-being at work among university staff and its influence on their work productivity. The study evaluated work well-being based on Seligman's (2018) PERMA Model. The sample group consisted of 105 staff members from a faculty at a university in Thailand. Participants were recruited through simple random sampling. The research instrument was a self-assessment questionnaire with an 11-point Likert scale, comprising a work well-being assessment and a work productivity assessment. Data were analyzed using descriptive statistics: mean, standard deviation, and multiple regression. The results revealed that university staff had a good level of well-being at work across the aspects of positive emotion, relationships, engagement, meaning, achievement, and health. Negative emotion and loneliness at work were rated at a slightly low level. The results from multiple regression indicated that negative emotion, achievement, meaning, and health could predict 51.7% of the variance in work productivity at a statistical significance level of p < .001. Negative emotion was found to have the greatest impact on work productivity. These findings can benefit the university's human resource development initiatives, particularly in self-emotional management training, which would benefit both staff well-being and university productivity.