The spacing effect is one of the most robust and replicable phenomena in psychological science, and holds promise for improving children's learning outcomes in educational settings. However, there is a striking limitation in the literature: very few studies have been conducted with young children (0–5-year-olds). Moreover, most studies examine children's learning on the group level, whereas early curricula typically focus on both group and individual outcomes. We predict that developmental and individual differences in visual attention, memory, prior knowledge, and metamemory will affect children's learning on massed and spaced schedules. Thus, we argue that the next critical step in research on the spacing effect is to develop a developmental and individual differences account. Indeed, this account will address limitations in theory and barriers in implementing the spacing effect in early educational settings.