The purpose of this study was to evaluate the psychometric properties of the Differentiation of Self Inventory-Revised (DSI-R) and Mental Health Inventory-18 (MHI-18), and to determine whether the Bowenian construct of differentiation could predict general mental health. In a sample of 322 Filipino adults, exploratory factor analysis (EFA) and regression analysis were performed to determine the construct validity and strength of associations between key variables. Results of the EFA for both measures indicated a new three-factor model for the DSI-R and two factor model of the MHI-18. Results of regression analysis indicated that self-differentiation and its dimensions positively predicted mental health, suggesting that highly differentiated individuals tend to display better overall mental health. Implications to theory, practice, and directions for future research are discussed.