PIEZO2 is a stretch-gated ion channel that is expressed at high levels in somatosensory neurons. Humans with rare mutations in the PIEZO2 gene have profound mechanosensory deficits that include a loss of the sense of proprioception. These striking phenotypes match those seen in conditional knockout mouse models demonstrating the highly conserved function for this gene. Here, we review the ramifications of loss of PIEZO2 function on normal daily activities and what studies like these have revealed about proprioception at the molecular and cellular level. Additionally, we highlight recent work that has uncovered the surprising functional and molecular diversity of proprioceptors. Together, these findings pioneer a path toward determining how the detection of mechanosensory input from muscles and tendons is used to control posture and refine motor performance.