Nils Rustung Mugaas (1921 - 1992) was a Norwegian trade unionist and civil servant.
He chaired Statstjenestemannskartellet from 1969 to 1974 and Statens Personaldirektorat from 1974 to 1990. Statens Personaldirektorat was abolished after 1990, but was succeeded by a department in the Ministry of Government Administration and Labour led by a Government Director of Personnel.
He was born in Ullensvang.[1] He grew up in Ostereidet, and resided in Bærum for the last 24 years of his life. Mugaas was politically active in the Labour Party.[2] [3]