Acceptance and commitment therapy (ACT) is an innovative psychological intervention emphasizing psychological flexibility and values-driven actions to enhance overall well-being. Unlike traditional cognitive-behavioral therapies (CBT), which often focus on altering maladaptive thoughts and behaviors, ACT encourages the acceptance of negative thoughts and emotions while fostering a commitment to personal values. This review explores ACT's effectiveness in promoting psychological well-being (PWB) by encompassing emotional, psychological, and social dimensions. Key aspects of PWB include emotional regulation, life satisfaction, and the reduction of experiential avoidance. The theoretical foundations of ACT are based on relational frame theory (RFT), which addresses cognitive fusion and experiential avoidance as central contributors to psychological distress. Extensive research, including meta-analyses and randomized controlled trials (RCTs), supports ACT's efficacy in treating various psychological issues and improving PWB. Despite strong empirical support, several gaps remain, including the need for more longitudinal studies, the exploration of cultural adaptability, and research on specific populations. Recommendations for future research include examining the long-term effects of ACT, its application across diverse cultural contexts, and its efficacy among underrepresented groups. This review underscores ACT's potential as a versatile therapeutic approach, providing valuable insights for mental health professionals and researchers.