This study investigated Model United Nations (Model UN), a simulation of the United Nations that is adapted for academic purposes and includes elements of discussion, negotiation, presentation, and engagement with global issues and international affairs. When students participate in Model UN, they are referred to as country delegates and represent different countries on different committees. As delegates, they join in discussions on global issues related to such topics as world conflict, international security, human rights, and education. In Model UN, student participants from diverse linguistic and cultural backgrounds, collaborate and interact in a common language (English) spoken differently among participants to deepen their understanding of current world issues. By so doing, they reflect on their intercultural communicative competence summarized as the ability to interact with people from another country and culture in a foreign language. Following a Model UN semester course at a Japanese university and a Model UN conference held in Japan, interview sessions with Model UN student participants were moderated and recorded to understand their learning attitudes and experiences of studying in the Model UN context. The interview data were used to generate themes for thematic analysis. The study concluded that Japanese Model UN student participants’ interactions with other learners of English from different cultural backgrounds allowed them to reflect on their intercultural communicative competence and, thus, be able to develop tolerance towards language-related misunderstandings.