The role of the teacher is vital in promoting a classroom climate that supports student learning and social-emotional well-being. However, little consideration is given to offering interventions to support teachers in reducing stress and burnout that result in teacher turnover. Studies have concluded mindfulness practices to be an effective intervention for teachers to reduce stress, increase emotional regulation, and promote well-being. The restrictions resulting from the global COVID-19 pandemic caused many educational institutions to shift to a distance learning model. The applications of online mindfulness for classroom teachers are just beginning to be explored, with few studies investigating the effects of online mindfulness training for teachers. The purpose of this case study was to examine teacher perceptions of mindfulness, stress, and self-efficacy following a district-led online delivery of mindfulness at a selected public school in southeast Texas. The study involved participants experienced with online delivery of mindfulness training in the school year 2020-2021 and who continued mindfulness practice in 2021-2022 school year. A mixed-methods research approach was used in this case study. The findings from the Five Facet Mindfulness Questionnaire- Short Form revealed awareness was statistically significant. Findings from the Perceived Stress Scale revealed 66% of participants had moderate stress levels. The Teachers' Sense of Efficacy Scale-Short Form findings revealed all the variables were statistically significantly different from how teachers perceived the delivery of teacher self-efficacy. [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/en-US/products/dissertations/individuals.shtml.]