Christian August Selmer (16 November 1816 – 1 September 1889) was a Norwegian lawyer and a magistrate.

He was the son of Johan Christian Selmer (1783-1830) and Johanne Ditlevine Michea Vibe (1788-1879).

Selmer's record as Prime Minister was characterized by conflict over whether members of the cabinet were required to appear in Parliament to answer questions.

He influenced King Oscar II to reject efforts at a compromise, setting the stage for impeachment proceedings.

Selmer was subsequently convicted under articles of impeachment and resigned as Prime Minister on March 1, 1884.