Background: Dental health problem among elementary students is a social and health problem which results in un-recoverable social, economical, cultural and health effects. This research is aimed to improve oral health among elementary students in Sanandaj city through theory of health belief model (HBM) and peer education approach.

  Method: This is a quasi-experimental research whichstarted byselecting three primary schools randomly. Peer education was assigned to educate the first group (n=30) and the second group was educated by trainer group (n=30) and the third was a control group (n=30). For each group, two questionnaires were completed before and two month after implementing education .The educational programs were based on (HBM) and were about knowledge on oral health and the importance of dental health problem and the way we can improve it. This program was carried out based on child to child approach and was a peer education program.

  Results : There were no statistical significant differences for mean score of knowledge (P= 0.726 ), perceived susceptibility (P= 0.758 ), perceived benefits (P = 0.898 ), perceived barriers (P= 0.950 ) and Cues to action(P= 0.950 ) among child to child group and trainer group. But Therewas a better practice of a child to child group in perceived severity (P= 0.002 ) and increasing use of toothbrush(P= 0.007 ) among students.

  Conclusion: The final statistical analyses showed that in improving oral health and use of toothbrush, which was the main goal of the research, peer education group was more than effective trainer education, However in many parts of health belief model there were no statistical significant difference s between child to child and trainer group . So it is recommended to use child to child approach for many health educational programs.