Reading assessment is a critical feature of education systems. The aim of this study is to explore reading assessment policy in the New Zealand (NZ) assessment culture. We reviewed research publications, national policy documents and test protocols on reading for year levels 6-9 (ages 9-13). We found that assessment data are broadly conceptualised and used for multiple purposes, that the representation of reading assessment data is located in an improvement-oriented environment and that the use of reading assessment for improvement purposes involves multiple actors and organisation levels. We discuss to what extent reading assessment policy supports student learning and teacher professional learning.