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Acoustic overexposure and aging can cause damage to mechanosensory structures and synapses in hair cells of the inner ear. Following noise exposures producing both temporary and permanent threshold shifts, 40-50% of cochlear inner hair cell synapses are rapidly lost with observable disarray, fusion, and loss of stereocilia. Aging mice also demonstrate a steady loss of synapses coupled with morphological changes to stereocilia including fusion, elongation, and internalization. Despite the concurrence of mechanosensory insult and synaptopathy, impaired transduction has not been implicated as a mechanism contributing to the loss of hair cell synapses. Here, I investigate the role of mechanosensory transduction in synapse development and maintenance by evaluating synapses of inner hair cells and vestibular otolith organs across multiple developmental timepoints in the presence of altered or absent transduction and after gene therapy aimed at restoring mechanosensory transduction. I utilize several mouse models with genetically induced defects in mechanosensory transduction including those with targeted deletion of Tmc1, Tmc2, or both, Spinner mice lacking the Tmie gene, and Beethoven mice carrying a missense mutation in Tmc1. I first assess the efficacy of a novel gene therapy strategy involving a unique injection technique and novel viral vector and show the strategy successfully transfects nearly 100% of inner hair cells and vestibular hair cells. I then demonstrate inner hair cells in mice lacking mechanosensory transduction undergo exuberant synaptogenesis during the first postnatal week and a drastic decline in synapse numbers over the following few weeks. Utilizing the novel gene therapy strategy, I find recovery of mechanosensory transduction leads to synapse preservation in Tmc mutant mice and significant recovery of ABR thresholds. Finally, I characterize vestibular synapses in Tmc mutant mice and demonstrate these synapses undergo changes that are distinct from those observed in the cochlea. I also measure VsEP thresholds to provide further evidence for vestibular dysfunction in mice lacking Tmc1, Tmc2, or both. Together, these data provide insight into the complex relationship between mechanosensory transduction, synaptogenesis, and synaptopathy, and suggest dysfunction of mechanosensory transduction contributes to cochlear and vestibular synaptopathy.