INTRODUCTION: Little is known about what factors predict student engagement in learning communities (LCs). At our institution, we recently converted from an informal, unfunded program with volunteer mentors and no participation requirement to a formal, funded program with a structured curriculum, dedicated mentors, and required attendance. We sought to identify factors that predict student engagement in this new program. METHODS: Medical students from all 4 years were invited to complete a survey that included self-rating of their level of engagement with their LC. We hypothesized that student engagement would be (1) higher in the new, formal program compared with the informal program; (2) lower among older students; and (3) higher among students who value collective activities for stress management. RESULTS: In total, 75% of students completed the survey. Students who participated in the formal LC program reported significantly higher engagement than those who experienced the informal version. Older, out-of-state, and underrepresented in medicine (URiM) students reported lower levels of engagement compared with younger, in-state, and non-URiM students, but gender and campus assignment were not associated with level of engagement. Students who valued participation in extracurricular activities, service work, and time with friends or family all had higher levels of engagement in LCs compared with those who valued more solitary activities. DISCUSSION: The formal, structured LC program was associated with higher levels of engagement than the informal program, and engagement was maintained throughout the 4-year curriculum. Subgroups of students reported lower engagement in LCs, and future research is needed to better understand and address this variability in engagement. This study is limited by the fact that students are only surveyed once annually, at a single institution, and our measure of engagement is brief and dependent on student self-report. In addition, it is not possible to discern from this study which components of the formal LC program were most strongly associated with high engagement.