The current research aimed at exploring the dynamic patterns of simultaneous change in EFL teachers and learners’ trait emotional intelligence (TEI) in a language classroom context. A reciprocal effects model was proposed to relate English as a foreign language (EFL) teachers to students’ TEI to suggest that there are positive reciprocal relationships between teachers’ and learners’ TEI. The model was tested with 4-wave longitudinal dyadic data (LDD) collected in the first 6 months of an academic year from 229 EFL teachers and 2016 learners. A dyadic curve of the factor model was used to analyze the data. Three research questions were formed to explore, firstly, the growth trajectories for teachers and their students’ TEI over time, secondly, whether the initial levels of teachers’ and students’ TEI predict linear change in TEI of teachers and students over time, and thirdly, whether teachers and their students’ trajectories (initial levels and slopes) of TEI were associated. The overall findings showed a slight increase in TEI in both dyad members over time. Also, a higher initial TEI was associated with more growth in TEI over time in both teachers and students. Finally, teachers who had a higher level of TEI at the beginning of the study showed were more likely to have students with an increasing TEI over time. This study is pioneering in providing longitudinal evidence for interactive emotion transmission between teachers and learners. Implications for prospective research and teacher education are provided. تفاصيل المقالة