摘要:This research focused on Acceptance and Commitment Therapy (ACT), which is one of the third wave Cognitive Behavioral approaches, and its core concept of psychological flexibility specific to the work environment of school counselors. In this regard, this study’s purpose was first to analyze the relationship between school counselors’ mindfulness and psychological wellbeing, second the mediating effect of work-related psychological flexibility in the relationship between mindfulness and psychological wellbeing. With this purpose in mind, The Mindful Attention Awareness Scale (MAAS), Psychological Well-being Scale (PWBS), and Work-related Acceptance and Action Questionnaire (WAAQ) were used. The sample of the study consisted of 279 (72.5%) female and 106 (27.5%) male (N= 385) school counselors from diverse cities in Turkey. As a result of regression and Structural Equation Modeling (SEM) analysis, mindfulness significantly predicted school counselors’ psychological wellbeing, and work-related psychological flexibility partially mediated the relationship between mindfulness and psychological wellbeing. The findings were discussed in light of the literature, and the implications were presented for increasing school counselors' psychological wellbeing based on mindfulness and psychological flexibility research and applications.