Marius Ormestad (13 December 1874 – 28 May 1964) was a Norwegian trade unionist and civil servant.

He was a son of artisan and farmer Johan Christian Ormestad and Hanna Karine Ryg.

[2] His father operated as blacksmith and watchmaker, in addition to running a small farm.

[2] An instrument maker, Ormestad started working for the company Elektrisk Bureau (manufacturer of telecommunication equipment) in 1890.

[2] Ormestad was manager of Oslo Trygdekasse from 1911 to 1944 and was a board member of the National Insurance Administration from 1935 to 1942.