Purpose: This study investigated the impact of contact-and education-based antistigma interventions on mental illness stigma, affirming attitudes, discrimination, and treatment seeking among college students. Methods: Data were collected from 198 students of a Chicago University campus in spring of 2014. Participants were randomly assigned to one of three conditions: a contact-based antistigma presentation, education-based presentation, or control condition. Measures of stigma, discrimination, affirming attitudes, and treatment seeking were administered at preintervention and postintervention. Results: A 3 x 2 analysis of variance was completed for each measure to examine condition by trial interactions. Both contact-and education-based interventions demonstrated a significant impact on personal stigma, perceptions of empowerment, discrimination, attitudes towards treatment seeking, and intentions to seek treatment from formal sources. No difference in effect was demonstrated between the contact-and education-based conditions. Conclusions: These findings suggest that these two approaches should be considered for challenging mental illness stigma among college students. (C) 2016 Society for Adolescent Health and Medicine. All rights reserved.