During adolescence, impulsivity usually escalates, increasing the risk of addiction and affecting academic achievement negatively. Mindfulness has been found to be one of the ways to regulate impulsivity, and emotion regulation can mediate the relationship between mindfulness and impulsivity. This research therefore aims to establish whether emotion regulation mediates the relationship between mindfulness and impulsivity amongst high school students. Quantitative research employing Hayes’ PROCESS mediation analysis was conducted. The participants, 390 Indonesian high school students aged 15-18, were collected using online questionnaires measuring mindfulness, impulsivity, and emotion dysregulation. The results show that emotion regulation partially mediated the relationship between mindfulness and impulsivity (ab = -.11, BootSE = 0.02, BootCI 95% [-0.16, -0.07]). Mindfulness increased emotion regulation skills, which in turn reduced impulsivity in high school students. The implications of the study are important in helping adolescents manage impulsiveness during the period of vulnerability to risk-taking. The use of mindfulness in schools could help manage the emotional and behavioral problems of high school adolescents.