At the start of the Kindergarten year in New South Wales (NSW) government schools, teachers gather information on several aspects of children's number knowledge to guide their teaching programs. This includes knowledge of the sequence of words used for counting, numeral identification, and using counting to solve problems. This study investigated the interaction between socio-economic disadvantage in NSW government schools and Kindergarten students' number knowledge on entry to school in 2013. There is a strong association between the measure of socio-economic disadvantage and the proportion of Kindergarten children starting school with limited number knowledge, underscoring the need for high quality early number programs in these communities.