Tord Hjalmar Ganelius (born 23 May 1925 in Stockholm, dead 14 March 2016 in Stockholm) was a Swedish mathematician and professor emeritus. He served as Permanent Secretary of the Royal Swedish Academy of Sciences and was a board member of the Nobel Foundation from 1981 to 1989. His primary research interests were holomorphic functions and approximation theory.
He was an Associate Professor at Lund University in 1953-56 and in 1957 he was appointed Professor of Mathematics at Gothenburg University, where he served until 1981. During this time he was Dean of the Faculty of Science twice, in 1963-65 and 1977-80. In 1972, he was elected a member of the Royal Swedish Academy of Sciences and he was appointed the permanent secretary in 1981, a position he held until 1989. He was a board member of the Nobel Foundation from 1981 to 1989, and every October he announced the Nobel Laureates in Physics, Chemistry and Economic Sciences.
In 1966, Ganelius published the Swedish-language mathematics textbook "Introduktion till matematiken", which since 2006 has been available on-line.