This chapter discusses the setting of standards for language learning in formal education and focuses in particular on the role that assessment plays in that context. Some challenging dilemmas that face educators in seeking to apply standards are discussed. In a globalized world, one such dilemma occurs when setting international standards while respecting diversity and the need for locally determined norms and context-specific policies and practices. Three specific meanings of standards and standardization are explored in relation to language education in formal schooling. These three key aspects of standardization are interrelated. Standard languages: what is to be taught and learned in school. Standards of proficiency: the levels of competence that is to be achieved as the outcome of language learning. Professional standards: how languages are taught and assessed and how the quality of the teaching and assessment is determined and monitored. These three meanings are explored by taking into account the context where the language learning takes place and in relation to the intended uses of the target language outside of the classroom; the challenge for policymakers and educators is ultimately a multilingual one that involves the languages used in the home, in civil society and in school as curriculum subjects.