The present studies examined the influence of two regulatory mode concerns—a locomotion concern with movement from state and an assessment concern with making comparisons [see Higgins, E. T., Kruglanski, A. W., & Pierro, A. (2003). Regulatory mode: Locomotion and assessment as distinct orientations. In M. P. Zanna (Ed.), Advances in Experimental Social Psychology (Vol. 35, pp. 293–344). New York: Academic Press]—on engaging in counterfactual thinking and experiencing post-decisional regret. When contemplating a decision with a negative outcome, it was predicted that high (vs. low) locomotion would induce less counterfactual thinking and less regret, whereas the opposite would be true for high (vs. low) assessment. Locomotion and assessment orientations were measured as chronic individual differences in Study 1 and 2, and were induced experimentally in Study 3. In Study 1 and 3 a purchase scenario with a negative outcome was used to elicit counterfactuals and regret, while in Study 2 participants were asked to recall one of their own personal purchases that had a negative outcome. The results supported our predictions. We discuss the implications of these findings for the nature of counterfactual thinking and regret from the perspective of their relation to regulatory mode