The purpose of this study was to examine how sharing styles and social skills relate to the development of same-sex friendships in universities. In 2011 and 2013, longitudinal surveys were conducted in July (Time1), November (Time2), and January (Time3). Fifty freshmen participated fully in these surveys. Cross-lagged effects models including “degree of satisfaction” indicated that “degree of satisfaction with their friendships” (Time2) decreased “sharing intentions” (Time3), while “degree of satisfaction” (Time1) promoted many styles of sharing (Time2). These findings show that some participants avoid sharing intentions because they prefer to maintain moderately satisfactory relationships. In addition, a negative effect of “sharing goods” was estimated from the result that “sharing goods” (Time1) decreased “degree of satisfaction” (Time2). A cross-lagged effects model including “depth of relationship” showed that “sharing relationships” (Time2) promoted “depth of relationship” (Time3). Moreover, the findings that “depth of relationship” (Time1) promoted “sharing feelings” (Time2) and “sharing feelings” (Time2) promoted “depth of relationship” (Time3) showed a mutual causal association.