Gongylonema is a genus of thread-like nematode that was 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). Some 38 species are known, about 12 of which have been recorded in Europe.