Abstract: This study administered both cross-sectional and longitudinal questionnaire surveys on 660 university students. Results of the study indicated the following: Social support had significant main effect on concurrent stress; those having relatively higher level of social support experienced significantly less concurrent stress than those having lower level of social support. After controlling for earlier stress, earlier social support no longer had significant main effect on later stress. Change of types of social support (four types all together: those continuously having high level support; those continuously having low level support; those having high level support at the beginning but change to low level support two years later; those having low level support at the beginning but changed to high level support two years later) also had significant main effect on later stress. Two types of personality, “open-assertive” and “reserved-gentle”, had significant main effect on concurrent stress, with the “open-assertive” experiencing significantly less stress than the “reserved-gentle” on every corresponding stress types. Earlier personality types still had significant main effect on stress level two-years-later. Social support and personality had significant both main effects and interaction effect on stress; change of types of social support and personality had significant both main effects and interaction effect on stress

Key words: stress, social support, personality, university students