This research examines the role of idiomatic expressions (IEs) in international business (IB) communication and non-native speakers’ (NNEs’) English proficiency. It investigates how IE affect IB communication’s effectiveness and whether IEs should be taught to NNE. We collected feedback from academics who confirmed the importance of IE and relevant business idioms from professional websites. We also assessed IE usage benefits for different cohorts working in IB settings. The results indicate that IE can enhance communication efficiency, cross-cultural social skills, monetary rewards, and satisfaction in IB. The findings support the need for teaching IE to NNE and justify inclusion in curricula.