Introduction: The management of asthma during adolescence has specific challenges and is likely influenced, to some extent, by the patient's belief in their ability to affect change, their self-efficacy. Bolstering self-efficacy could potentially improve an adolescent’s ability to self-manage their asthma. The aim of this study was to examine the effects of a triggers’ educational-modifying intervention on self-efficacy among adolescents diagnosed with asthma living in Iran. Methods: Sixty adolescents, aged 12 to 18 years, diagnosed with asthma participated in this randomized clinical trial. Participants randomly assigned to the control group received standard care while those assigned to the experimental group participated in a 5 week, nurse led, triggers modifying educational intervention in specialized clinics of lung in Tabriz, Iran. The self-efficacy scale developed by Bursh et al., was used for data collection. Results: The level of self- efficacy in two groups before intervention was not statistically significant, while the post intervention measures were statistically significant. Intervention was effective in improving adolescents’ self-efficacy. Conclusion: Since this type of intervention has the potential to improve Self- efficacy in adolescents with asthma, it is suggested that adolescence directly education about asthma triggers along with modulating triggers will be of value and parent‐centered could be diminished. The need for such interventions emphasizes in clinic and outpatient clinics