Introduction: Research related cases of bullying in elementary school-age children has limited. The purpose of this study was to analyze the factors of bullying behavior at Pungkuran Pleret Public Elementary School in Bantul. Method: This study uses a case study design. We applied a total sampling technique. All respondents were 102 students and a principal. We also conducted interviews with ten students obtained by purposive sampling. The instruments used included questionnaires for student habits at school, interview guidelines, telephones and observation sheets. Results: Verbal bullying (42.16%), physical bullying (39.22%), and relational bullying (48,04 %) done by student at elementary school in moderate category these male students. We found three critical themes causes bullying including impingement, ignorance and self-defense. Student express their feeling by veting their desires. Ignorance arises in students and school attitudes about bullying. Bullying done by elementary school students as a form of self defense in the environment. Conclusion: Bullying behavior by elementary school students can occur because of impingement on students who are wrong in expressing their desire, endurance and the ignorance of schools in bullying cases..