John Nesbitt (1925-1998) was a Manitoba agrologist. He worked as a university professor, and in 1970 challenged Israel Asper for the leadership of the Manitoba Liberal Party.
Born in Shoal Lake, Manitoba, Nesbitt saw service in World War II and subsequently obtained a Ph.D. from Penn State University in 1952. He was head of the department of Dairy Science at the University of Manitoba from 1953 to 1966, and was a respected public speaker. He was also a member of Manitoba's Milk Control Board from 1959 to 1970.
Despite having the support of House Leader Gordon Johnston, Nesbitt received only 329 votes at the provincial Liberal convention of 1970, as against 720 for Asper.
Nesbitt returned to the University of Manitoba in 1977, serving as Associate Director (and later Director) of the School of Agriculture. In 1984, he helped to found Keystone Agricultural Producers Inc. He never actually ran for office at the provincial or federal level.