Background Intergroup dialogue (IGD) is a prominent social justice pedagogy that engages diverse groups of students in sustained, facilitated dialogues on social issues. Decades of IGD research have informed the development of the critical–dialogic theoretical framework of intergroup dialogue, which describes how IGD engages students in communicative, cognitive, and affective processes that promote intergroup understanding, intergroup relationships, and intergroup collaboration and action. Scholars have recently highlighted the need to better understand the relationships between students’ developmental capacities, their corresponding attitudes and dispositions, and IGD processes and outcomes in order to discern how students at different levels of development respond to and experience IGD. Study Purpose Grounded in the theory of self-authorship, theories of epistemological development, and corresponding research suggesting that dispositions associated with students’ epistemological assumptions of knowledge and knowing can moderate students’ engagement and development in matters that are interpersonal and intrapersonal in nature, the purpose of this study was to analyze the relationships between students’ openness to multiple perspectives (a disposition associated with epistemological development) and the interpersonal and intrapersonal processes and outcomes associated with IGD. Research Design In this secondary data analysis of the multi-institutional, longitudinal dataset constructed as part of the multi-university intergroup dialogue research project, structural equation modeling was used to discern how the relationships between IGD's communicative, cognitive, and affective processes and outcomes vary for groups of students with different levels of openness to multiple perspectives. Results In line with previous research on college student development, the results of this study illuminate a moderating relationship between students’ openness to multiple perspectives and the intergroup processes and outcomes associated with IGD. The patterns of moderation observed suggests that IGD's communicative, cognitive, and affective processes and outcomes are most strongly (although not exclusively) associated with matters of pedagogy and cognition for students who are less open, and matters of communication and affect for students who are more open. Conclusions and Recommendations The results of this study suggest that as IGD facilitators are able to increase their understanding of epistemological development and related dispositions, pass on their understanding to their students via readings and activities, assess their students’ epistemological dispositions, and augment their preparation and facilitation accordingly, an IGD group's collective ability to increase intergroup understanding, relationships, collaboration, and action is enhanced. This can be accomplished as what is known about college students’ epistemological development and dispositions is more fully integrated into IGD curriculum, facilitation, and facilitator training.