This chapter explores what the field of interpersonal neurobiology has to teach us as psychotherapists about the role of human relationships, especially compassionate relationships, in health and well-being. Interpersonal integration—relationships in which connection links two unique and distinct human beings—stimulates the activity and growth of fibers in the brain that are integrated. The internal attunement may lead the brain to grow in ways that promote balanced self-regulation via the process of neural integration, which enables flexibility and self-understanding, empathy and compassion. In terms of the interpersonal neurobiology of mind, compassionate action, kind action, and empathic action are all integrative acts. Ancient contemplative practices may reveal a rigorous form of mental training that ultimately can be seen to promote such integrative states in body, mind, and relationships. So compassion and related emotional states are vital to promote the integration and self-organization of mind, brain, and body on which healing relationships like parenting, teaching, and psychotherapy depend.