Previous studies have shown the rate of domestic violence towards women in Indonesia is increasing. Researches in the field have found that one of the most effective ways to prevent the violence was the bystander. To understand the characteristics of bystander in the sample of teenager in Indonesia, this study seeks to determine the relationship between efficacy and Decisional Balance and likelihood to intervene. The result showed that there is a significant correlation between bystander efficacy and tendency to intervene, yet no empirical support for Decisional Balance.