| Dr. James Merritt Harrison | |
| Birth Date: | 20 September 1915 |
| Birth Place: | Regina, Saskatchewan |
| Death Place: | Canada |
| Citizenship: | Canadian |
| Field: | Geology |
| Work Institution: | Geological Survey of Canada Canadian Federal Department of Energy, Mines and Resources |
| Alma Mater: | University of Manitoba Queen's University |
| Known For: | Founding the Union of Geological Sciences |
| Prizes: | Order of Canada Logan Medal (1969) |
James Merritt Harrison, (September 20, 1915 – July 6, 1990) was a Canadian scientist and public servant. He was the Director of the Geological Survey of Canada from 1956 to 1964, and Assistant Deputy Minister of the Department of Energy, Mines and Resources.
Born in Regina, Saskatchewan, he obtained his B.Sc. from the University of Manitoba in 1935. He received his M.A. in 1941 and Ph.D. in 1943 from Queen's University.
He was one of the founders of the Union of Geological Sciences (IUGS) and was its first President from 1961 to 1964. Between 1966 and 1968, he was President of the International Council for Science (ICSU).
In 1969, Harrison was awarded the Logan Medal, the Geological Association of Canada's highest honour.
From January 1973 to March 1976, he was the Assistant Director-General for Natural Sciences at the United Nations Educational, Scientific and Cultural Organization in Paris.
In 1971, he was made a Companion of the Order of Canada.