Imperial Oil Limited (French: L'Impériale) is a Canadian petroleum company. It is Canada's second-biggest integrated oil company. Exxon Mobil Corp. had a 69.6 percent ownership stake in the company as of December 31, 2012. It is a significant producer of crude oil, diluted bitumen and natural gas, Canada’s major petroleum refiner, a key petrochemical producer and a national marketer with coast-to-coast supply and retail networks. Its retail operations include Esso-brand service stations and On the Run/Marché Express and Tiger Express-brand convenience stores. It is also known for its holdings in the Alberta Oil Sands. Imperial owns 25 percent of Syncrude, which is one of the world’s largest oil sands operations. Imperial is also in a joint venture oil sands mining operation with ExxonMobil Corp., called Kearl Oil Sands.

Currently headquartered in Calgary, Alberta, Imperial Oil was based in Toronto, Ontario, until 2005.

Most of Imperial's production is from its vast natural resource holdings in the Alberta Oil sands and the Norman Wells oil field in the Northwest Territories.

The company was incorporated in London, Ontario, in 1880 (Filey 1998:62). The company's association with ExxonMobil dates back to 1898 when the then-Standard Oil of New Jersey acquired controlling stake in Imperial Oil.

Imperial Oil discovered the Leduc Woodbend Devonian oil reef in 1947, marking the beginning of the contemporary period in Canadian oil and gas development. Drilling began on the landmark discovery well Leduc No. 1 on November 20, 1946.

In 1989, Imperial Oil acquired Texaco's Canadian operations.

From the 1934-35 season through the 1975-76 season, Imperial Oil was a sponsor of the Canadian Broadcasting Corp. program Hockey Night in Canada for both radio and television broadcasts.

In February 2013, Richard Kruger, President of ExxonMobil Production Co. and a Vice President of Exxon Mobil Corp., was appointed to be Chief Executive of Imperial Oil. His predecessor, Bruce March, left to become senior vice president of global operations for ExxonMobil Chemical Co.

Besides Richard Kruger, other members of the Board of Directors of Imperial Oil are Krystyna Hoeg, Jack Mintz, David Sutherland, Darren Woods, Sheelagh Whittaker and Victor Young.

Imperial Oil has 1700 service stations with majority owned third parties and sold 497 stations in 2016. In the late early 1990s Imperial Oil acquired retail operations from Texaco's Canadian unit Texaco Canada Incorporated.

With ExxonMobil having majority ownership, Imperial Oil uses its parent company's brands, including the Esso name for service stations, On the Run for convenience stores, and the Speedpass electronic payment system.