Here we describe “Brain development of deductive reasoning” a pediatric neuroimaging dataset freely available on OpenNeuro.org. This dataset includes neuroimaging and standardized assessment data from 56 participants aged 8.47–15 years. Functional Magnetic Resonance Imaging (fMRI) data were collected while participants completed both set-inclusion and linear-order deductive reasoning tasks. A subset of participants (n=45) returned two years later for follow-up standardized assessment testing allowing for future research to investigate individual change in cognitive and academic skill. Previous research on this dataset has not examined the relation of skill and demographic measures to the neural basis of reasoning. Moreover, these studies have not examined the relation of the neural basis of reasoning to that of arithmetic or differences between children and adults in the neural basis of reasoning. Therefore, there are many opportunities to extend the research in the published reports on this data.