This article discusses the role of vocabulary learning in supporting multilingual students' participation in disciplinary practices and discourses in K-12 content-area classrooms. First, the authors discuss the strengths and limitations of incidental and intentional vocabulary learning. They then propose a new approach to vocabulary instruction in particular and disciplinary language development in general: "embedded teaching." This approach has three key characteristics: (1) prioritizes students' engagement in sensemaking in the disciplines; (2) defines the language of school as encompassing everyday as well as disciplinary discourses; and (3) leverages both incidental and intentional vocabulary learning. The article illustrates the embedded teaching approach through examples that show how it can support multilingual students' understanding of language in the disciplines. The authors foreground the importance of paying attention to students' evolving understanding of disciplinary concepts, supporting the expression of student agency, and developing students' metalinguistic awareness.