The blood–brain barrier (BBB) restricts the delivery of therapeutics into the central nervous system (CNS). This limitation is due largely to localization of drug transport mechanisms to the brain endothelial cells (BECs). Although mammalian and in vitro models are currently used to study drug transport, zebrafish (Danio rerio) are advantageous for dissecting complex biological problems such as the BBB. This report focuses on zebrafish as a suitable model system for studying the BBB and drug transport.