Introduction :Adolescent are vulnerable to get negative influenced as substance abuse. Therapeutic group therapy and assertiveness training are nursing intervention that is expexted to increased substance abuse refusal skill in adolescent. The goals oh the research to determine the effect of therapeutic group therapy and assertiveness training against substance abuse refusal skill in Junior High School.

Method : The research design is quasi-experimental pre-posttest without control group and 87 adolescent in Junior High School was chosen by using purposive sampling technique. Instrument in this research is using Drugs Avoidance and Self Efficacy Scale (DASES) which is used to measeure of substance abuse refusal skill. Data were analyzed using central tendency, paired t test, and repeated ANOVA.

Result : The results showed significantly increased of substance abuse refusal skill after therapeutic group therapy and assertiveness training (p >0.05).

Conclusion: Nursing intervention using therapeutic group therapy and assertiveness training is recommended to increase substance abuse refusal skill who can prevent substance abuse in adolescent.