Australia and New Zealand have participated in the Organisation for Economic Co-operation and Development's Programme for International Student Assessment since 2000. Reading literacy was the main focus of the Programme for International Student Assessment in 2000, and at that time both countries' students generally performed well above the Organisation for Economic Co-operation and Development average. Nearly 20 years later, in the latest cycle of the Programme for International Student Assessment in 2018, reading literacy was again the main focus. Students' average reading performance has tracked down in both countries. Large inequities persist between socio-economically advantaged and disadvantaged students, indigenous and non-indigenous students, and genders. The Programme for International Student Assessment gathers a wealth of contextual information that highlights key educational challenges facing both countries, including poor disciplinary climates, declining attitudes towards reading and sense of belonging at school, and increasing bullying. While there are similarities among the two countries' 15-year-olds, evidence shows practices are diverging at the middle primary schooling level, which may be impacting positively on younger Australian cohorts; these differences are also discussed with respect to early reading experiences.