John Patrick Gallagher (July 16, 1916-December 16, 1998) was a Canadian geologist and businessman. Born in Winnipeg Gallagher attended the University of Manitoba. He became a petroleum geologist working for a number of multinationals in California, Egypt, Latin America and Canada searching for oil.

In 1950 he branched out on his own and founded Dome Petroleum. The company found important new oil fields in Alberta, but Gallagher's main focus was on Canada's arctic. The company spent billions exploring and found large deposits under the Beaufort Sea, but did not have the money to develop them. Deeply in debt Gallagher resigned as CEO in 1983. Dome was sold to Amoco in 1988. Gallagher found a new company that would become Prima Energy in 1984.

Gallagher was an Officer of the Order of Canada and a member of hte Canadian Petroleum Hall of Fame.