This article outlines a proposal for evaluating educational policy and planning for multilingual school systems. Often, debates on language policy in education suffer from a restricted perspective that elevates socio-political considerations above all others. Assigning secondary importance to language learning constraints and developmental principles of second language learning renders the discussion incomplete and incoherent. Bilingual instructional models need to be based on current research findings that prioritize both an early introduction of content-based second language instruction (immersion), and the development of higher-order language abilities through a language that children understand.