Abstract: Recent theories claim that prediction – the pre-activation of representations during language processing – supports language development, and a number of empirical findings support this view. However, prediction’s role in development is debatable. For example, while individual differences in prediction correlate positively with vocabulary size, the directionality is unclear: Prediction may be a cause or a consequence of developmental changes. Here, I present 3 experiments that contribute to this ongoing debate. Findings suggest that prediction and comprehension emerge concurrently in infancy (experiment 1), that infants’ prediction abilities correlate positively with their vocabulary size (experiment 1), and that prediction and comprehension are distinct language processing mechanisms (experiment 2). Furthermore, in an ongoing longitudinal study (experiment 3), we are evaluating whether infants’ prediction abilities forecast their developmental outcomes 12 months later. Taken as a whole, these novel findings suggest that prediction supports both language processing and language development.