In recent years, institutions have responded to changing school populations by preparing teachers for the growing number of emergent bilingual learners (EBLs). But this preparation largely focuses on supporting students' academic learning and language development, despite enhanced attention to social-emotional well-being in wider educational circles. This comparative case study seeks to understand whether and how teachers are prepared to facilitate this integral component of student learning in five schools with linguistically diverse populations and varied program models to serve EBLs. We first probe how teachers draw from various facets of their preparation to support EBLs' social-emotional well-being, including teacher education, professional development, collaboration with colleagues, and personal experiences. We then consider teachers' and students' perspectives on the requisite expertise to facilitate well-being in classrooms. Findings provide insight for university, district, and school stakeholders seeking to enhance teacher preparation as a means to improve the educational experiences of EBLs.