Jan Jakob Tønseth (1 September 1947 – 12 October 2018) was a Norwegian author, poet and translator. He was born in Oslo. Tønseth's first poetry collection was "Kimærer" in 1971, published when he was 24 years. He was known for his novel trilogy "Hilmar Iversens ensomhet" (1992), "Et vennskap" (1997) and "Resignasjon og portvin" (2002). Tønseth was a member of Norwegian Academy for Language and Literature.