Although the contribution of family support and peer support to university adjustment has been examined separately, few attempts have been made to explore the mechanism underlying this relation. This is the first study in the Asian context to test the role of self-esteem in mediating the effect of social support on first-year university adjustment outcomes. Self-esteem is a measure of one's positive or negative attitudes toward oneself (Rosenberg, 1965). Higher self-esteem is vital to a variety of developmental outcomes in early adulthood, such as the transition to university, whereas lower self-esteem has been related to poorer adjustment (Hickman, Bartholomae, & McKenry, 2000). Perceived self-esteem stems from social attachments to others that reflect positively on oneself and provide interpersonal support (Friedlander, Reid, Shupak, & Cribbie, 2007). High self esteem developed as a result of social support from family and peers may increase individuals' belief in their ability to solve problems, leading to better university adjustment. The authors hypothesized that self-esteem mediates the impact of family support and peer support on university adjustment. The participants in this study were 418 first year university students (mean age 19.94 years; 65% female) at an education university in Hong Kong, China, offering mainly education related subjects. As expected, findings showed that first-year university students receiving greater family and peer support reported better adjustment outcomes overall, which provides additional evidence of the universally beneficial effects of multiple support figures on university adjustment. Such findings corroborate the previous argument that parental support plays an important role throughout adolescence and early adulthood, even as reliance on support from peers increases.