This longitudinal study examined whether social self-efficacy and self-disclosure serve as mediators between attachment and feelings of loneliness and subsequent depression. Participants were 308 freshmen at a large Midwestern university. Results indicated that social self-efficacy mediated the association between attachment anxiety and feelings of loneliness and subsequent depression, whereas self-disclosure mediated the association between attachment avoidance and feelings of loneliness and subsequent depression. These relationships were found after controlling for the initial level of depression. A total of 55% of the variance in loneliness was explained by attachment anxiety, social self-efficacy, and self-disclosure, whereas 42% of the variance in subsequent depression was explained by the initial level of loneliness and depression. Implications of the findings for enhancing freshman adjustment are discussed.