Divorce is often accompanied by feelings of guilt toward the former spouse. So far, no scale has been available to measure such feelings. For this purpose, the authors developed the Guilt in Separation Scale (GiSS). Content validity was assured by using experts and lay experts to generate and select items. Exploratory analyses were run on samples of 214 divorced individuals and confirmatory analyses on 458 individuals who were in the process of divorcing. Evidence was provided for the reliability and construct validity of the GiSS. The internal consistency was high ([alpha] = 0.91), as were the 6-month and 12-month test-retest reliabilities (r = 0.72 and r = 0.76, respectively). The GiSS was related to shame, regret, compassion, locus of cause of the separation, unfaithfulness, and psychological functioning. (Contains 2 tables and 4 footnotes.)