Background: Adolescence is a crucial period marked by profound physical, emotional, and social changes, often leading to heightened stress, anxiety, and emotional fluctuations. There is a worrying rise in mental health issues such as anxiety and depression among adolescents, impacting their school performance, friendships, and future prospects. Mindfulness-Based Interventions (MBIs) have gained attention for their potential to enhance mental health by promoting present-moment awareness and emotional regulation. This study aims to investigate the effects of the implemented mindfulness-based module on participants' emotion regulation, psychological well-being, life satisfaction, and happiness. Methods: A randomized controlled trial (RCT) design was implemented, with eighty participants selected through purposive sampling and randomly assigned to either an experimental group or a control group. The experimental group participated in structured mindfulness sessions over five weeks, while the control group received no intervention. Pre-intervention, post-intervention, and follow-up assessments were conducted using the Emotion Regulation Questionnaire (ERQ), Psychological Wellbeing (PWB) Scale, Satisfaction with Life Scale (SWLS), and Oxford Happiness Questionnaire (OHQ) to measure changes in emotion regulation, psychological well-being, life satisfaction, and happiness. Results: The analysis of covariance of the data indicated a significant effect of the mindfulness-based intervention on the posttest and follow-up scores for emotion regulation, psychological well-being, life satisfaction, and happiness among adolescents. Conclusion: The study has uncovered insights into how mindfulness-based interventions achieve their effects. Moreover, it has collected valuable data that can shape future practices and aid in devising strategies to promote emotional and psychological well-being among adolescents.