In February 2015, all New Zealand schools moved to assessing English Language Learners (ELLs) using the English Language Learning Progressions (ELLP) to determine eligibility for additional funding to support these learners. This paper firstly provides the background to the current assessment situation, and summarises the literature regarding key principles of assessment. It then describes key guidelines made available to schools by the Ministry of Education for using the new assessment system, particularly the use of Overall Teacher Judgements (OTJs). The paper then presents findings from interviews with three primary school English language specialist teachers regarding their experiences with using the new system, known as ‘ELLP assessment’. The gaps that exist between the literature, Ministry guidelines, and ESOL teacher practice are described, and recommendations are made for bridging these gaps. Currently little is known regarding teacher practice in regard to ELLP assessment, so this study fills a gap in the literature relating to the assessment of young ELLs in the New Zealand context.