With increasing numbers of young English language learners (ELLs) entering schools in English-speaking countries, assessment of their English language proficiency has become important for screening, placement, and diagnostic purposes, as well as for ongoing formative and summative assessment. A key assessment event for teachers in New Zealand schools, particularly those with large numbers of ELLs, is the twice-yearly ‘ELLP Assessment’, in which ELLs’ language skills are rated against descriptors in the English Language Learning Progressions (ELLP) (Ministry of Education, 2008). This assessment is high stakes because the results determine whether a school receives Ministry of Education funding for additional support of ELLs. As ELLs are placed in mainstream classrooms in New Zealand schools, it is important that mainstream teachers, who generally have no specialist training for working with ELLs, are equipped with strategies and tools to accurately assess ELLs’ language skills. This paper reviews the literature regarding the use of, and issues associated with, classroom-based oral language assessment of ELLs in ESL contexts. It then summarises the New Zealand Ministry of Education guidance for assessing oral language proficiency for ELLP assessment, and also describes a number of guidelines, strategies and tools from other English-speaking countries which have been designed to facilitate teacher assessment of ELLs’ oral language proficiency. Finally, the paper discusses the potential usefulness of oral language assessment strategies from other countries for mainstream teachers in the New Zealand context who are required to complete ELLP assessment.