This study aimed to investigate the impact of the flipped classroom model on students' self-efficacy and the difference in self-efficacy between males and females using this model. In order to accomplish this, 66 advanced participants were selected from a private English language institute. They were divided into two equal groups, namely experimental (flipped classroom) and control (traditional) group. The students' self-efficacy was scored before and after the intervention with the Self-Efficacy Survey. The results indicated an increase in their average self-efficacy score with the flipped classroom while the traditional classroom decreased their average score. When the genders were analyzed separately, the males demonstrated a decrease in self-efficacy while the females indicated an increase while utilizing the flipped classroom. In light of these results, some recommendations have been made.