Positive emotions have been shown to shape individuals' reactions to intergroup conflicts, but the exact mechanism remains unknown. The current research hypothesizes that the impact of positive emotions would be moderated by dialectical thinking: beliefs about accepting contradiction and change. Experiencing positive emotions in an intergroup conflict may be perceived as unacceptable and evokes discomfort among nondialectical individuals, amplifying the negative reactions toward outgroup members. In contrast, because dialectical thinkers accept contradictory emotions, positive emotions may buffer against the adverse consequences of intergroup provocations. Study 1 confirmed this hypothesis by examining Chinese emotions in a real-life and a lab-induced intergroup conflict. Study 2 recruited Western participants and demonstrated that the moderating effect of dialectical thinking was evident only under a conflict-related context. Study 3 confirmed the causality by manipulating dialectical thinking in a historically enduring conflict. These findings suggest that enhancing dialectical thinking maximized the buffering effect of positive emotion against intergroup conflict. (PsycInfo Database Record (c) 2020 APA, all rights reserved).