Recent technological advances have enabled ever more detailed characterizations of neuronal subtypes. Here, immunohistochemistry and unbiased single-nucleus RNA sequencing was used to identify several human cortical GABAergic neuronal subtypes that possess distinct molecular signatures and transcriptomes. One notable subtype had ‘rosehip’-like axonal boutons and inhibited backpropagating action potentials in pyramidal neuron dendrites; these neurons are thus likely to be involved in local regulation of dendritic computation.