Appreciating the research on teacher emotions is integral to understanding successful teaching and learning in P-12 classrooms. However, systematic research on teacher emotions is relatively new and diverse, emerging since the 1990s across a variety of fields. Using the research from the past three decades, this entry describes four major areas of practice involving teacher emotions in classrooms: (1) creating supportive classroom environments; (2) building student–teacher relationships; (3) socializing emotions; and (4) supporting teacher emotion competencies. These areas of practice are used as an organizational framework for providing research-based examples to emphasize the integral nature of teacher emotions for student learning, motivation, and well-being.