The purpose of this article is to demonstrate how mental health practitioners can use the Enneagram's system of human personality development as a source of insight and a tool for personality transformation. The article provides an introduction to the Enneagram and its orientation to personality types and defines a linear process of how to use the Enneagram with clients. Mental health practitioners can use the Enneagram to help clients develop a deeper understanding of their personality styles and those of others to move forward with needed cognitive and behavioral changes, thereby effectuating productive relational change.