Zebrafish (Danio rerio) have emerged as a promising model for assessing nanomedicines because of their fecundity, physiological and anatomically similarity to mammals, optical transparency and genetic malleability. Zebrafish can be used to predict the toxicity, systemic circulation, biodistribution and therapeutic efficacy of nanomedicines, therefore can act as an efficient alternative vertebrate screening model to decrease the number of experiments in higher vertebrates. In addition, the model is proven to be cheap and can quickly screen nanomedicines under in vivo conditions thus bridging the gap between in vitro and rodent studies. In this review, we highlight the potential of utilizing zebrafish as a model organism for preclinical investigation of nanomedicines with respect to toxicology, pharmacokinetics and therapeutic efficacy.