The capacity to communicate via acoustic signals is prevalent across the animal kingdom, from insects to humans. What are the neural circuit mechanisms that underlie this ability? New methods for behavioral analysis along with an unparalleled genetic toolkit have recently opened up studies of acoustic communication in the fruit fly, Drosophila melanogaster. Its nervous system comprises roughly 100,000 neurons, yet flies are able to both produce and process time-varying sounds during courtship. Just as with more complex animals, sensory feedback plays an important role in shaping communication between the sexes. Here, we review recent work in Drosophila that has laid the foundation for solving the mechanisms by which sensory information dynamically modulates behavior.