This study explored the relationships between an individual's interpersonal functioning, perceived spirituality, and selected spiritual practices. Using Bowen's family systems theory, the authors proposed that an individual's level of spiritual development and level of differentiation are correlated and that certain spiritual practices are predictive of both of these levels. The results of this study showed a positive correlation between differentiation and a general report of spirituality. Spiritual practices also predicted individuals' level of spiritual development. A common underlying concept, self-regulation, may explain the correlation between differentiation and spiritual development. Likewise, spiritual practices may support change in both areas. (Contains 2 tables.)