We explored associations among teachers' self-reported enjoyment for teaching mathematics, science, and English language arts (ELA) and their students' self-reported behavioral engagement in each content area, and how these associations varied depending on student sex and socioeconomic status. Participants included 33 fourth grade teachers and 443 students from 14 schools in the Southwestern U.S. Multiple regression models with cluster-robust standard errors was used. Models regressed students' content-area engagement on teachers' content-area enjoyment, controlling for students' initial engagement in that content area and other relevant covariates. Teachers' ELA and mathematics enjoyment were each positively associated with students' engagement in each content area, and an interaction effect was detected in mathematics whereby lower-SES students with low-mathematics-enjoyment teachers reported lower mathematics engagement. Findings extend recent research highlighting teachers' emotions, and more specifically positive emotions, as factors that can be leveraged to support student learning, as well as provide more nuanced information about the contexts and student groups for whom these processes may be most relevant. [This paper will be published in "School Psychology."]