This qualitative study investigated the language ideologies and instructional practices of an entire Spanish language faculty at a high school in a new gateway state for immigration. The study examined additive and subtractive practices of teachers as they strived to teach Spanish to heritage language learners (HLLs) enrolled in mixed Spanish-as-foreign-language classes (that is, classes comprised of both HLLs and traditional second language learners). The study found that although at the philosophical level teachers had additive, pluralistic views of acculturation, they often opted for instructional practices that contradicted their philosophies. This article deconstructs those practices and outlines the fundamental shifts in ideologies that are necessary to promote effective and culturally appropriate instruction for HLLs in mixed classes.