Background: Smoking behavior is a global health threats til today. The number of active smoker among adolescents aged 12-18 years old in DI Yogyakarta keeps on increasing even thoung there are number of smoking prevention and smoking cessation program have been done by the government. one of the methods that can be applied to address the issue of smoking behavior is by self-help group. Purpose: The purpose of this study was to examine the effect of Self-Help Group Toward Motivation to Quit Smoking in the program study of machine faculty engineering 2015 Generation at University Muhammadiyah of Yogyakarta Reseach Method: This was a quasy experimental study with pre-post test using control group. The sampling method was non-probability sampling with random sampling method. Thrty two respondents participated in this study and they were divded into control group and experimental group. The data were collected by using valid (r=0,666) and reliable (r=0,846) Ricmond Test motivation questionnaire. Wilcoxon test and Mann-Whitney test were used to analizy the data. Results: The result of the study showed that most of the respondents who participated were 17 years-old. There was significant motivation improvement among the control group. There was significant motivation improvement among experimental group after the intervention (p<0,05, t=0,000). Conclusion: in conclusion self-help group is effective to improve the motivation to quit smoking in the program study of machine faculty engineering 2015 Generation at University Muhammadiyah of Yogyakarta