Social–emotional learning interventions are intended to improve classroom dynamics and have the potential to enhance the well-being of students and their teachers. Using data drawn from an effectiveness trial of the Social Skills Improvement System SEL Edition Classwide Intervention Program (SSIS SEL CIP; Elliott and Gresham in SSIS SEL Edition Classwide Intervention Program manual, Pearson, Inc., 2017), the present quantitative study explored associations between classroom implementation of a universal SEL program, teachers’ emotional well-being, and teacher–student interactions. The results from a sample of 80 first- and second-grade teachers located in three socioeconomically and geographically diverse regions of the USA indicated that implementation of the SSIS SEL CIP curriculum was positively associated with teachers’ classroom organization skills at the end of the year. Findings also revealed an interaction between treatment condition and teacher emotional well-being such that control teachers with lower well-being also had lower quality classroom organization but this association did not exist for teachers in the intervention condition. Findings suggest that implementation of the SSIS SEL CIP may help to preserve positive teacher–student interactions even when teachers are reporting lower levels of emotional well-being.