Few studies are reported on the effectiveness of drama-based intervention program on illicit drug prevention. The objectives of the study were to develop a drama intervention program based on Theory of Planned Behavior (TPB) among junior high school students. This study includes an experimental group of 31, on-campus control group of 36, and off-campus control group of 31. The experimental group received drama-based illicit drugs prevention program for 6 weeks while the control group received no intervention. The experimental group showed improvements in attitude, subjective norm, perceived behavioral control and behavioral intention. On the other hand, the control group didn’t show any favorable results. This study demonstrated the effectiveness of school-based illicit drug prevention program incorporating TPB and drama teaching.