Teachers' classroom management has serious implications for teachers' well-being, job satisfaction (Gale et al., 2021), burnout (Aloe Amo & Shanaha, 2014), and student outcomes (Gage, 2019). Understanding how teachers build self-efficacy for classroom management offers insights into how to provide better classroom environments for students, increase teacher retention, and sustain teacher longevity in the profession. Teachers' classroom management self-efficacy references their beliefs in their capacity to manage the classroom environment and create spaces where students learn and flourish. This correlational survey study investigated the relationship between novice teachers' perceived classroom management efficacy and the sources of their classroom management efficacy. Bandura's (1977) teacher self-efficacy theory provided the guiding theoretical framework. Tschannen-Moran and Hoy's (2001) "Teacher's Sense of Efficacy Survey" and Pfitzner-Eden's (2016) "Sources of Efficacy" survey were simultaneously administered to 104 middle school teachers to address the question of whether there is a relationship between classroom management efficacy and the sources of efficacy. Multiple linear regression analysis revealed that teachers' perceptions of their classroom management efficacy (CME) correlated to the sources of efficacy; more specifically, mastery experience and verbal social persuasion were the only sources positively significantly correlated to CME and physiological states was negatively significantly correlated, suggesting that to equip beginning teachers with the skills and expertise to manage student behavior and classrooms effectively rests in providing contexts in which to develop mastery experiences with CME. The existence of a moderate correlation between the sources of efficacy and CME suggests that there may yet be other characteristics at the individual level or school level that mediate the sources of efficacy and influence teachers' perceptions of their CME. Future studies should investigate mediating influences of other variables on teachers' CME. [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.]