The automobile industry, specifically the Canadian division of General Motors, has always been Oshawa's lifeblood. Founded in 1876 as the MacLaughlin Carriage Company, General Motors of Canada's headquarters and major assembly plants are located in the city. It is also home to Windfields Farm, a thoroughbred horse breeding operation and birthplace of Canada's most famous racehorse, Northern Dancer.

Two nuclear power plants are also located in the area, and a new university, the University of Ontario Institute of Technology, opened in Oshawa in 2003.

Oshawa is a major urban center onto itself, containing several suburbs in its Census Metropolitan Area. Nevertheless, it is still considered part of the Greater Toronto Area.