Jon Lyng (19 April 1945 – 16 February 2003) was a Norwegian lawyer and politician for the Conservative Party.
He was born in London as a son of John Lyng. A lawyer by profession, he is best known as the defender of Arne Treholt in 1984–1985, together with Andreas Arntzen and Ulf Underland. In politics, he was a State Secretary in the Ministry of Justice and the Police from 1985 to 1986. He was a member of Oslo city council from 1983 to 1991, and chaired his local party branch from 1992 to 1996.[ He was also chair of Oslo Kino from 1988 to 1991 and 1996 to 2003.]