The burnout rate of educators is a growing concern, leading to high turnover rates and a negative impact on student achievement. Mindfulness-Based Stress Reduction (MBSR) is a promising intervention to address this issue. This study aimed to examine the effectiveness of MBSR on self-efficacy and professional-efficacy in K-12 teachers. A quantitative quasi-experimental study, including pre-and post-intervention questionnaires, was utilized. A paired-sample t-test was calculated to compare the mean of the emotional exhaustion pretest score to the mean post-test score. The mean of the pretest was 32.70 (sd=10.13), and the mean of the post-test was 27.35 (sd=6.84). A statistically significant increase from the pretest to the post-test was found (t (22) = 3.24, p < 0.05). Similarly, A paired sample t-test was calculated to compare the mean of the personal accomplishment pretest score to the mean post-test score. The mean of the pretest was 28.91 (sd=0.46), and the post-test was 31.43 (sd=67.41). A significant decrease from the pretest to the posttest was found (t (22) = -2.312, p < (0.05). The study has implications for teacher training programs and school administrators implementing MBSR to retain and support teachers in the classroom. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]