Past studies have shown a relationship between self-leadership and performance in the fields of business management, sports, clinical psychology, employee performance and education. But is self-leadership also relevant to the unique field of missionary work when it comes to effectiveness and performance? Follow the case study of a missionary couple in Cambodia who effectively achieve their goals within seven years in the field. From this real-life example, discover how leadership effectiveness and performance is achieved through the practice of thought self-leadership (TSL) and the four cognitive processes: management of self-talk, mental imagery, beliefs and assumptions, and thought processes.