Anyone can experience traumatic events. Among them, in particular, interpersonal trauma involves more
serious issues. In terms of the fact that university students are the driving force leading our society, it is
essential to investigate not only the relationship between their interpersonal traumatic experience and happiness
but also protective factors which affect the relationship. The purpose of the study was to investigate moderating
effect of posttraumatic growth between interpersonal trauma and happiness. 181 university students were utilized
by analyzing moderated multiple regression. Data were gathered from 181 undergraduate student in 4-year
university in Korea. In order to verify the moderating effect of posttramatic growth and the relationship between
interpersonal traumatic experience and happiness, the hierarchical regression analysis is utilized. The study is
mainly based on 3 scales; interpersonal trauma, happiness, and posttraumatic growth. The major findings of the
study were as follows ; First, the study showed a significant relationship between interpersonal trauma and
happiness. To be specific, group bullying was found to have exercised a negative influence on happiness, whereas,
severance of relationship was found to have exercised a positive influence on happiness. Second, it showed that
posttraumatic growth moderated the relationship between interpersonal trauma and happiness. Second,
posttraumatic growth does not present any moderating effect on the relationship not only between the experience
of witness the death and happiness but also severance of relationship and happiness. However, the study reveals
that there is meaningful moderating effect on the relationship between group bullying experience and happiness.
Based on these findings, the study discussed the different effects of group bullying and severance of relationship
on happiness. Moreover, the discussion suggests that an intervention by consultants or a counselling program is
recommended for students who have a group bullying experience. At the end of the study, methods that could
bring awareness of posttraumatic growth on university students, who suffered from interpersonal trauma, were
also discussed.