Abstract: A flexible shaft coupling is disclosed in which hub members each having a plurality of axially directed peripheral teeth are adapted for mounting on the shafts to be coupled. In one embodiment, the grooves between the teeth are provided with a rounded bottom and a serpentine grid element interconnects the hub members. The grid element has a circular cross section and includes rungs which are seated in the grooves of both hub members. In other embodiments more than one layer of rungs having circular cross sections are seated in the grooves. The grooves may also have side walls which diverge radically outwardly, and the outer layers of rungs may have a greater diameter than the radially inner layers.