Malfred Kasper Bergseth (19 June 1895 – 24 August 1966) was a Norwegian trade unionist. He was born in Øvre Rendal. He was a manual laborer from a young age, mostly in construction. He organized both politically and trade-wise in 1912, joining the Norwegian Union of General Workers and . In 1917 however he left social democracy to become a syndicalist, in Norsk Syndikalistisk Forbund. He became known as manager of Oslo sten, jord og cementarbeiderforening in 1927, a union he had joined in 1923. In 1930 he became deputy chairman of the Norwegian Union of Building Industry Workers. He later chaired the union.