Recent educational policy reforms have reinvigorated the conversation regarding the role of language in the science classroom. In schools, the Next Generation Science Standards have prompted pedagogical shifts yielding language-rich science and engineering practices. At universities, newly required performance-based assessments have led teacher educators to consider the role of academic language in subject-specific teaching and learning. Simultaneous to these policy changes, the population has continued to diversify, with schools welcoming students who speak hundreds of different languages and language varieties at home, despite English continuing as the primary medium of instruction in science classrooms. Responding to these policy and demographic shifts, we have designed an innovation to prepare teachers and teacher candidates to design instruction that promotes students’ disciplinary language development during rigorous and meaningful science instruction. We add a language lens to the widely used Understanding by Design® framework, emphasizing inclusion and integration with what teachers already do to design science curriculum and instruction, rather than an add-on initiative that silos language development apart from content learning. This language lens merges the principles of culturally and linguistically responsive practice with the three stages of backward instructional design to support educators in designing effective and engaging science instruction that promotes language development and is accessible to the growing number of students from linguistically diverse backgrounds.