Low persistence and high attrition rates in science, technology, engineering, and mathematics (STEM) are major challenges in higher education, particularly among underrepresented students. Therefore, it is important to identify barriers and examine strategies aimed at improving persistence, retention, and student completion in STEM courses and programs. Research has indicated that a fixed mindset can limit and influence a student's perception of themselves, their behavior, and their short- and long-term persistence, often resulting in withdrawal, disengagement, and other behaviors that result in academic failure. Communities of practice (CoPs), an ongoing, often yearlong professional development opportunity for faculty, have been identified as a promising practice to help faculty develop and use teaching strategies that foster a growth mindset in students. Using a quasi-experimental design, I evaluated a CoP at a community college that had incorporated a growth mindset component to determine if faculty participation in the CoP impacted student grades in STEM courses. I conducted two factorial ANOVAs, one focused on condition (pre-CoP and post-CoP) and gender and another on condition and race. Results indicated there was a significant difference in student grades in STEM courses, with students performing better in courses after faculty participated in the CoP (M = 3.05; SD = 1.20 ) than before faculty participated in the CoP (M = 2.71; SD = 1.32). There were no main effects for race or gender. There were two interaction effects, with males performing better postfaculty participation in the CoP compared to prefaculty participation in the CoP and with males performing better postfaculty participation in the CoP compared to female performance in prefaculty participation in the CoP. Findings are discussed in the context of prior literature and recommendations and resources for those interested in implementing or enhancing a CoP are provided. [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.]