The purpose of this study is to investigate the relative influence of ego-resiliency and social support of parent and peer on high school students’ subjective well-being. The subjects consist of 406 students in a high school located in Gyeonggi Province. The data were analyzed by analysis of variance (ANOVA) and standard multiple regression using SPSS 12.1. The findings illustrated that the relative effect of ego-resiliency and social support of parent and peer on subjective well-being of high school students varied according to their grades. Among the independent variables, social support of the parent was the most influential predictor for the 9th grade students’ subjective well-being. However, the 10th grade students were mainly affected by both ego-resiliency and social support of parent and peer in a similar proportion. For 11th grade students who are about to take the college entrance exam, ego-resiliency was the most influential predictor for their subjective well-being. This means that ego-resiliency is strongly helpful to overcome in the hardship and difficulties for the high school students.