This study aims to investigate the effect of a psychoeducation program on the high school students’ emotion regulation skills and their mindfulness levels. This experimental research study adopted a pre-test post-test research design with experimental and control groups. The study group of the research was composed of 30 students (15 in experimental group, 15 in the control group) studying in a high school in Erzincan in the second semester of the 2018-2019 academic year. While a 12-session psychoeducation program designed for the experimental group was applied in the study, any intervention was not conducted for the control group. The data were collected with the Difficulties in Emotion Regulation Scale (Gratz & Roemer, 2004), Mindful Attention Awareness Scale (Brown & Ryan, 2003), and the Psychoeducation Program Evaluation Form (Deniz, 2017). The data were analyzed with two-way analysis of variance. The findings showed that when examined the effects of the prepared psychoeducation program on the experimental groups, it was found that emotion regulation skills and mindfulness levels increased significantly, and these differences were also observed in the follow-up measurements.