University campuses are critical spaces where the importance of diversity, equity, and inclusion (DEI) in society are discussed, and debated. However, even as campus communities across the world grow more diverse, higher education institutions are facing an existential crisis--high dropout rates, low enrollments, growing disenchantment with education, and issues of otherization, sexism, and racism on campus. It has never been more necessary for administrators, faculty, staff and all stakeholders to understand the role of effective institutional, intergroup, and individual communication in increasing students' university belongingness, and positively affecting their attitudes towards 'others.' Using the lens of systems theory and intergroup contact theory, this study analyzes how institutional, interpersonal, and individual level factors affect college students' attitudes about diversity, and their university belongingness. An online survey of 432 students from a midsized public university in the U.S. indicated that specific interpersonal communication (e.g., interactions with diverse faculty and peers), as well as institutional-level factors were positively correlated with student attitudes towards diversity. Results also indicated that microaggressions were a significant predictor of belongingness as were institution-level communication where students felt they had university support or when they felt their voices were heard. Other findings indicated that students of color felt less welcome on campus and reported lower university support than their Caucasian peers. Results highlighted both areas of hope, as well as key challenges for higher education administrators. Implications, including recommendations for student success, greater intercultural collaboration, and creating a more inclusive campus community, are discussed. Some key implications include the need to recruit more international and culturally diverse staff; offering DEI courses, regular DEI training of staff, and actively promoting campus activities that encourage greater intergroup contact.