From 1951 and from 1947 he was Vice President of the Swedish branch of
Save the Children International, then was a board member of the International Cooperative Alliance 1947–1981, concurrently serving as Chairman of
UNICEF at the international level from 1970 to 1972. Thedin joined the board of the
Swedish International Development Cooperation Agency in 1963 and was Chairman of the publishing company Liber from 1964. He was also Chairman of
Sveriges Radio from 1967, chairman of the Correspondence School 1969–1976, for the board of the
East Asian Museum 1970–1977, for the
Swedish Handicrafts Association 1968–1970, for the Swedish Coop Center 1976–1978, vice-chairman of the Norwegian State Museums of Art 1977–1979,
International Union for Child Welfare 1977–1978, chairman of the working committee for International children's year 1978–1979, and project manager for the
International Labor Office in
Bangkok 1979 -1984. == Publications ==