Inga Margarethe Thorsson, née Sjöbäck (3 July 1915 – 15 January 1994) was a Swedish politician (Social Democrat).

Thorsson represented Sweden in the United Nations General Assembly and served as a delegate to several UN bodies, playing a key role in international disarmament and development initiatives.

Thorsson was born on 3 July 1915 in Malmö, Sweden, the son of Eduard Sjöbäck and his wife Edith (née Bagger-Jörgensen).

Thorsson was commissioner (borgarråd) in the social welfare department from 1958 to 1962, and expert at the Ministry for Foreign Affairs from 1962 to 1963.

Furthermore, Thorsson was the chief negotiator regarding international population and environmental issues from 1972 to 1975, and chairperson of the Swedish delegation at the Committee on Disarmament in Geneva from 1974 to 1982.