Background: Depressive symptoms often occurred during the adolescence period. This situation affected their psychological well-being, which is an important element for a positive youth development. Thus, there is an urgent need to prevent such mental health problems and promote psychological health outcomes among adolescents. Mobile health has been created as a platform to promote mental health to adolescents to ensure ongoing safety and effectiveness. Despite the positive evidence to support the mobile health, tailored mobile health to promote mental health and prevent psychological symptoms among adolescents in Thailand is lacking.This study aimed to assess the feasibility and acceptability of delivering digital technology intervention prototype called “MU-My-Mind Mobile Application (MU-My-mind App)” among Thai adolescents and evaluate the efficacy of this application in improving psychological health outcomes. Materials and Methods: This quasi-experimental research was conducted in secondary school students in Thailand. A convenience sample was recruited and participants were asked to download the MU-My-Mind App on their smart phone. Health outcomes were also evaluated by self-administered questions and focus group interview at baseline and post-intervention. Feasibility and acceptability were assessed. Quantitative data were analyzed by descriptive statistics and pair t-test. Qualitative data were analyzed by thematic analysis. Results: Thirty students completed the MU-My-Mind application. Quantitative data suggested significant improvements on mindfulness, psychological well-being, depression, anxiety and stress. Qualitative data derived into six themes: a) overall feedback of the program, b) learning to manage stress and challenges, c) elevating relaxation responses and calmness, d) heightened mindfulness and concentration, e) increased awareness and management of emotions, and f) altering perspectives and managing thoughts. Overall, data suggested the acceptability and feasibility of the intervention. Conclusion: The “MU My Mind Mobile Application” prototype was demonstrated feasible and well acceptable among Thai adolescents to promote their psychological health outcome. However, there are some limitation and suggestion emerged during this pilot testing. Future research should be explored in a larger sample size with comparison control group and over a longer duration with a range of diverse samples to ensure the efficacy of this application.