Southern Tsimshian, Sgüüx̣s[note 1] (pronounced: /skiːxs/[9]) or Sgüümk,[7] is the southern dialect of the Tsimshian language, spoken by the Gitga'ata and Kitasoo Tsimshians in Klemtu, B.C.

It became extinct with the death of the last remaining speaker, Violet Neasloss.

Sgüüx̣s is close to Coast Tsimshian and has been described[10] as a highly conservative dialect, however the two may not have been mutually intelligible with Coast Tsimshian.

[11] The name Sgüüx̣s means "the language beside."

Specialist John Asher Dunn wrote several articles on the language,[12] from which the term Southern Tsimshian arose.