Striatal neurons within the basal ganglia play a central role in vertebrate action selection; however, their location in larval zebrafish is not well defined. We assayed for conserved striatal markers in the zebrafish subpallium using fluorescent in situ hybridization (FISH) and immunohistochemistry. Whole mount FISH revealed an inhibitory neuronal cluster rostral to the anterior commissure that expresses tac1, the gene that encodes the precursor peptide for substance P. This molecular profile is shared by mammalian striatal direct pathway neurons. A second partially overlapping population of inhibitory neurons was identified that expresses penka, the gene that encodes the precursor peptide for enkephalin. This molecular profile is shared by striatal indirect pathway neurons. Immunostaining for substance P and enkephalin confirmed the presence of these peptides in the subpallium as well as the presence of dopaminergic innervation. The tac1 and penka populations were both found to increase linearly across larval stages. Together, these findings support the existence of a striatal homologue in larval zebrafish that grows to match the development and increasing behavioural complexity of the organism.