The purpose of this study was to evaluate the psychometric properties and cross-cultural validity of the Differentiation of Self Inventory-Revised (Skowron & Schmitt, 2003) and Mental Health Inventory-18 (Veit & Ware, 1983) and to determine whether the Bowenian construct of differentiation could predict general mental health. In a sample of 322 Filipino adults, exploratory factor analyses and regression analyses were performed to determine the construct validity and strength of associations between the two concepts. Results of the EFA suggested a new three-factor model (3F-DSI-R) for the DSI-R while supporting the original two-factor model of the MHI-18. Regression analyses indicated that self-differentiation and its dimensions are significant predictors of mental health. Findings suggest that highly differentiated individuals tend to display better overall mental health. Lastly, implications for theory, practice, and directions for future research are discussed.