The research reported in this article was conducted from a socio-environmental perspective on learners' school readiness when entering Grade 1, as well as their school performance in Grade 1 and again in Grade 4. The relation between school readiness and performance in Home Language and Numeracy in Grade 1, and performance in the same learning areas in Grade 4 were investigated by means of a longitudinal quantitative study. One school in the Free State province was purposefully selected. The Aptitude Test for School Beginners (ASB) was implemented to capture school readiness, including school maturity and levels of development in physical, cognitive, emotional, social and normative domains. Results confirm that school readiness significantly correlated with academic performance of the respondents in Grade 1 as well as with their school performance in Grade 4.