The present study was directed to explore the levels of psycho-social development, and emotional and behavioral characteristics manifested by those who are involved in bullying at school. For 450 out of 1212 students of the 4th to 7th grade, self ratings were congruents with peer nominations in status for school bullying and so further analyses were based on their data. The participants were partitioned into four groups (bully, victim, bylly/victim, and comparison group) and completed the Self-Image Questionnaire for Young Adolescents and the Child Behavior Checklist. Results indicated that the comparison group reached the higher level of psyco-social development than the other three groups. However, the bully group had somewhat self-esteem, whereas the victim and the bully/victim group had typical dysfunctional problems. In particular, the worst bully/victim group formed very derogatory family relationships. Finally, the bully group manifested physical aggressions and the victim group related to a lack of self-control and show-off behavior. These results suggest that different service programs should be required for different groups.