Evidence suggests that facilitated interventions in study abroad enhance gains in intercultural development, but many recent studies are not generalizable due to small numbers and lack of experimental design. In this study, subjects received individual or small-group interventions online in a course with trained intercultural mentors. The authors analyzed pretest-posttest changes on an intercultural assessment, the Intercultural Development Inventory, for treatment groups and a control for between-group differences. This study corroborates previous findings on the effectiveness of mentorship in study abroad and offers innovations for scaling up institutional efforts to support intercultural learning to reach larger numbers of students.