This section addresses the theoretical foundations of the concept of psychological flexibility and examines its developmental process. Psychological flexibility is an important personal ability necessary for individuals in both their daily and professional lives. In social life, it affects an individual's personal development, interpersonal relationships, and even health; while in professional life, it plays a significant role in relationships with colleagues, coping with organizational problems, and solving work-related issues. Psychological flexibility is considered the opposite of psychological rigidity. Psychological rigidity is a process that prepares the ground for the emergence of psychopathology. An individual's inability to cope with unwanted experiences in life, acting according to rigid cognitive patterns, being unable to focus on the present moment due to past experiences and future anxieties, distancing themselves from their values, and exhibiting behaviors outside of their values all result in psychological rigidity. At this point, psychological flexibility is considered a fundamental personal characteristic that provides solutions to these problems. The development of psychological flexibility takes place through the six core processes of Acceptance and Commitment Therapy. These processes are: Acceptance, cognitive dissociation, focus on the present moment, contextual self, values, and resolute action are key processes. These processes act as a barrier against psychological rigidity, enabling individuals to be more resilient in the face of challenges based on their internal experiences and circumstances. Uncertainty, for individuals, is associated with novelty, complexity, and insolubility, leading to increased anxiety and decreased performance. Psychological flexibility, an individual trait, allows individuals to cope with difficult situations by accepting the situation, focusing on the present moment, maintaining their values, and creating a balance between performance and negative performance.