The purpose of the current study was to examine the validity and reliability of (Journal of Marital and Family Therapy 2003, 29, 209) Differentiation of Self Inventory-Revised (DSI-R; Skowron & Schmit, 2003) in Turkish adults. The DSI-R was translated, independently back-translated, and revised. Two independent samples of adults over the age of 25 were used. The original 46-item DSI-R was not supported by the data derived from Sample 1 (n = 221). However, a revised 20-item, four-factor model fit the data well. This 20-item model was subsequently cross-validated with a second sample of Turkish adults (n = 187). Scale scores showed adequate internal consistency, 5-week test–retest reliability, and satisfactory convergent and criterion-related validity. It was concluded that Turkish DSI-R (DSI-T) is a valid and reliable measure to assess an individual's differentiation level. In light of the findings, implications for the use of the DSI-T and ideas for future research are discussed.