Teachers working in middle and high school Dual Immersion (DI) programs (Spanish-English) face unique sets of challenges: linguistic equity between the two languages of instruction, attrition due to high linguistic and academic expectations, and preparing DI students for standardized tests in English. In this article, we reflect on our current experiences both from the teacher preparation perspective and from daily teaching and learning in DI classrooms. From the intersection of our positionalities and lived experiences, we conceptualize the next steps in the preparation of future Dual Immersion (Spanish-English) secondary teachers. In doing so, we outline the specific skills middle and high school DI teachers must have in order to build effective practices around three key areas for Dual Immersion instruction: Bilingualism and Biliteracy, Student Achievement, and Socio-Cultural Competence. We argue that in order to guarantee the success and high quality of DI programs in middle and high school, Teacher Preparation Programs and School Districts should work together now developing a comprehensive and intentional preparation and support for middle and high school DI teachers and administrators working in these school sites.