Gongylonema is a genus of thread-like nematode that was discovered in 1850 by Joseph Leidy and described by Molin in 1857. It is the only currently valid genus in the family Gongylonematidae, though the mysterious Spiruroides – usually placed in the Subuluridae, which are not closely related to Gongylonema among the Spiruria – might actually belong here. They are parasites of birds and mammals, transmitted by insects (especially beetles).