Teachers are responsible for delivering academic instruction, facilitating student learning and engagement, and managing classroom behavior. Stress may interfere with performance in the classroom, however (Tsouloupas, Carson, Matthews, Grawitch, & Barber, 2010), and recent studies suggest that stress is quite common among today's educators. In light of these trends and their potential for negatively impacting students' learning, it is critical to identify factors that support educators' health, wellbeing, and effectiveness. The Prosocial Classroom Model (Jennings & Greenberg, 2009) suggests that mindfulness and other aspects of social-emotional competence may lead to more effective classroom management and protect educators from experiencing a "burnout cascade" of deteriorating classroom climate, student misbehavior, and emotional exhaustion. Mindfulness has been defined as "paying attention in a particular way: on purpose, in the present moment, and nonjudgmentally" (Kabat- Zinn, 1994, p. 4), and mindfulness training for adults has been linked with reductions in stress and improvements in wellbeing (Ospina et al., 2007). Emerging evidence from intervention studies suggests that mindfulness training is associated with improvements in teachers' classroom behavior (e.g., Flook, Goldberg, Pinger, Bonus, & Davidson, 2013; Jennings, Frank, Snowberg, Coccia, & Greenberg, 2013). In a central Pennsylvania middle school setting, the authors examined how educators' mindfulness at the beginning of the school year predicted change in educators' self-reported efficacy with respect to student engagement, classroom management, and instructional practices from fall to spring of the school year. Two tables are appended.