The purpose of this study is to determine the effect of peer education on HIV/AIDS on the knowledge and sexual risk among grades 9 to 12 high school students in Tampilisan National High School, Tampilisan, Zamboanga del Norte. This is a quasi experimental one group pre and post interventional study. This study includes 150 respondents. Twenty-five students were given peer education training wherein 16 students completed the training. These trained peer educators gave lectures to their grade 9 to 12 peers. A 2-part questionnaire was utilized for this study. It consisted of a 17-item knowledge section and a 15-item Sexual Behavior Inventory. Results revealed an increase in the knowledge mean scores from pretest (11.05) to posttest1 (12.72) and posttest2 (12.6). Results of the sexual risk assessment revealed that 14 (41.17%) respondents who were previously at a low risk status changed to a moderate/high risk status. On the other hand, 4(3.4%) who were previously at moderate/high risk changed to a low risk status after the intervention. (p-value 0.03389). The study concludes that peer education was effective in increasing the knowledge of grade 9 to 12 students regarding HIV/AIDS however, it is not effective in decreasing the sexual risk of the respondents.

Keyword: HIV Sexual risk Grade 9