The goal of this qualitative single case study was to explore the effects of expressive writing as a self-regulation strategy in a suburban high school algebra classroom for reducing self-reported math anxiety. A variety of stressors related to the school environment impact adolescents, including peer dynamics, stress from the high school transition, and math anxiety (Becker-Blease, 2017; Iimura & Taku, 2018; West et al., 2014; Yamani et al., 2018). Students who cannot manage stressors effectively may suffer in their academic performance and class engagement. One strategy that has been found to lower students' math anxiety is expressive writing (Hines et al., 2016; Park et al., 2014; Rozek et al., 2019; Shen et al., 2018). Expressive writing is "the technique of writing a deep and meaningful piece about a personally significant topic" (Shen et al., 2018, p. 2). Research was still needed on the effects of expressive writing on ninth grade algebra students in a suburban school district. The expressive writing strategy was implemented during the first five minutes of class for three days a week, every other week, over the course of six weeks. Data collection included interviews, questionnaires, and observations. Students participated in interviews before and after the six-week portion of the study, sharing their past math experiences, feelings about math, workload, and experiences in the transition to high school. Questionnaires were completed at the end of class periods to collect data on students' feelings about the lesson and the expressive writing activity. Observations were conducted to look for student engagement. The common themes that emerged from the data included students' experiences with the expressive writing protocol, main stressors or workload, feelings about math, experiences in the high school transition, ability to look for support, and the impact of COVID-19. The findings of this study showed that students shared more positive feelings about math after participating in the expressive writing activity, which indicated that expressive writing was an effective strategy for teachers to support ninth grade students with math anxiety. Further research is needed on the effects of expressive writing over a longer time and in other content areas. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]