Abstract
As workplaces increasingly recognise the importance of employee mental wellbeing, research into psychological flexibility and psychological inflexibility (PF/PI) has grown. PF, rooted in Acceptance and Commitment Therapy (ACT), is the capacity to pursue valued goals despite stressors and internal challenges, whereas PI reflects rigid attempts to avoid or control unwanted internal experiences, even when doing so undermines wellbeing or goal pursuit. Our systematic search across five databases identified 88 studies that had examined the relationship between PF/PI and wellbeing in workplace contexts. The findings indicate a surge in research since 2020, with PF (and, as such, PI) predominantly measured using the Acceptance and Action Questionnaire-II (AAQ-II). Most studies focus on mitigating negative wellbeing outcomes, such as burnout and psychological distress, rather than fostering positive wellbeing. PF/PI research is concentrated in high-stress professions, particularly healthcare, with limited exploration in other sectors. Finally, PF/PI research is dominant in Western research. Recommendations for future research directions were established, including a clearer construct definition, development in measurement approaches, longitudinal and intervention-based designs and broader occupational and cultural representation. Ultimately, this review highlights the need for a more nuanced and precise understanding of PF/PI to optimise its role in enhancing workplace wellbeing.