Mosquitoes use their keen sense of smell to identify key resources in the environment. This sense relies on olfactory receptors expressed in hundreds of sensory neurons scattered across the antennae and maxillary palps. Until recently, it was assumed that individual sensory neurons express just one tuning receptor—as is the rule in both vinegar flies (Drosophila) and mice. However, a decade of bulk RNA sequencing shows that there are many more receptors present in adult mosquito olfactory organs than can be accounted for by this one neuron–one receptor rule. To reconcile these observations, we have generated the genetic tools necessary to sort and sequence the transcriptomes of tens of thousands of single neurons from Aedes aegypti antennae. We recover nearly all ~60 types of olfactory sensory neuron and characterize the precise patterns of receptor expression/co-expression therein. Our results have important implications for odor coding and olfactory system evolution in this important disease vector mosquito.