This report from Sobrato Early Academic Language (SEAL) presents a framework and guidance for practice for the success of students who are English learners (ELs) or dual language learners (DLLs). It focuses on the developmental phase, ages 3–8, for language, literacy, learning, and identity, and places an emphasis on supporting deeper learning and development. SEAL’s P–3 framework articulates a set of pedagogical and system-design principles that derive from the knowledge base on effective practices for ELs or DLLs, culturally and linguistically sustaining approaches, research on dual language development, and experiences building systems that appropriately serve immigrant and dual language communities and enable effective practices to be implemented.