This paper synthesizes research on student and teacher emotions in the classroom through the lens of the Ecological Dynamic Systems model. It places emotions in immediate contexts in the classroom including emotionally expressive environment, learning/instruction, and relationships. The paper identifies specific antecedents of emotions within each context. It further discusses how the intersection of classroom events and teachers' and students' goals, beliefs, and relational experiences give rise to emotions. Emotions in the classroom further reflect the complex transactions between classroom and socio-historical contexts. The paper discusses how emotions are influenced by broad socio-cultural factors including educational policies and reforms, school demographics, and culture at large. Finally, it focuses on the role of appraisal for the emotions in the classroom and how appraisals are contextualized by students' and teachers' beliefs and personal experiences. Understanding the interplay of various contexts for emotions in the classroom will inform teacher preparation, designing instructional and behavioral interventions as well as educational policies and reforms.