The aim of the current randomized controlled study was to evaluate treatment adherence of children and adolescents who visited an outpatient psychiatry clinic and started medication for the first time, with telehealth application. This study was performed with parents of patients who visited the clinic from October 1, 2020, to March 31, 2021. Data were collected using a personal information form, Medication Control Form, and Morisky Medication Adherence Scale via telephone after verbal and written consent were obtained. It was found that 96.7% of participants in the experimental group had high medication adherence, whereas 93.3% of participants in the control group had low medication adherence. Results show that telehealth application is effective in maximizing adherence to treatment among children and adolescents.