This thesis used Astin's (1993) I-E-O framework to explore how participation in a living-learning program as well as other college environments affected college students' mental health. Data from seven unique institutions that administered an additional mental health module as a part of the 2008 and 2009 National Study of Living-Learning Programs were used in this study. Independent samples t tests, chi-squared tests, and multiple regression were the statistical methods used to investigate three research questions with Keyes et al. (2008) Mental Health Continuum - Short Form (MHC-SF) as the dependent variable. The final predictive model explained 33.5% and 37.6% of the variance in students' MHC-SF scores in 2008 and 2009, respectively. Findings did not evidence a predictive relationship between students' participation in a living-learning program and their mental health. Several aspects of the college environment favorably predicted students' mental health, including ease with transition to college, socially supportive residence hall climate, self-confidence, sense of belonging, and sense of civic engagement. Other variables unfavorably predicted students' mental health, including identification as lesbian, gay, or bisexual, as well as emotional consequences of alcohol use. This study's findings offer implications for practitioners and directions for future research.