ABSTRACT Background: Intolerance of uncertainty is a well-known predictor of post-traumatic stress symptoms following a traumatic event. At the same time, it is relatively unknown whether intolerance of uncertainty amplifies the effects of other adverse life events on PTSD symptoms among traumatized individuals. Objective: This article addresses this problem in a study of Ukrainian war refugees’ experiences with post-migration discrimination and powerlessness (loss of control). Method: 4972 forced immigrants from Ukraine took part in the study (90.2% women, Mage = 40.4, SD = 12.5) completing the PTSD-8 scale, measures of post-migration discrimination and loss of control experiences, and intolerance of uncertainty. Results: Almost half of respondents (47.5%) have probable PTSD. Regression analysis confirmed that war-related experiences, as well as intolerance of uncertainty, post-migration loss of control and experiences of discrimination were significant predictors of self-reported PTSD symptoms. Also, intolerance of uncertainty weakly moderated the effects of experienced discrimination and control deprivation on self-reported PTSD symptoms, so that the effects of adverse post-migration experiences were more pronounced among individuals high in intolerance of uncertainty. Conclusions: Understanding the effect of post-migration experiences on war refugees’ mental health is crucial for developing improved acculturation policies and fostering a supportive environment for forced migrants.