The problem and the solution. Three Principles Psychology (TPP) is a psycho-educational approach gaining increasing popularity among leadership development professionals. This article describes the principles underlying this approach and it reports results of a qualitative case study of TPP practitioners and business executives who have participated in related coaching and/or training. Based on the analysis of interview results from the case, the article discusses, among other things, the following issues: TPP's role in improving leadership effectiveness; major strengths and potential shortcomings of TPP as a leadership development approach; and attempts to implement TPP as an operating philosophy of organizations. The article concludes with recommendations for further research and human resource development (HRD) practice. It should be noted that through its earlier developmental stages Three Principles Psychology has also been known as Psychology of Mind, Neo-Cognitive Psychology, and Health Realization.