The Gzhelian (/ˈʒɛli.ən/ ZHELL-ee-ən) is an age in the ICS geologic time scale or a stage in the stratigraphic column.

The top of the stage (the base of the Permian system) is at the first appearance of the conodont Streptognathodus isolatus within the Streptognathus "wabaunsensis" chronocline.

[5] Six metres (20 ft) higher in the reference profile, the Fusulinida species Sphaeroschwagerina vulgaris aktjubensis appears.

A candidate is a section along the Ussolka river (a tributary of the Belaya river) at the edge of the hamlet of Krasnoussolsky, about 120 kilometres (75 mi) southeast of Ufa and 60 kilometres (37 mi) northeast of Sterlitamak (in Bashkortostan).

[6] The Gzhelian Stage is subdivided into five biozones, based on the conodont genus Streptognathodus: