Imperial Oil Limited (French: Compagnie Pétrolière Impériale Ltée) is a Canadian petroleum company.

[13] Englehart aimed to emulate John D. Rockefeller and merge the entire Canadian oil industry into one conglomerate.

[19] Imperial Oil's charter noted that its goal was to "find, produce, refine and distribute petroleum and its products throughout Canada.

[20] In 1883, the Victor works was struck by lightning and burned to the ground, and under Englehart's direction, the company concentrated its refining efforts at Petrolia.

[22] Frasch had taken the position primarily to supervise the installation of his refining method at the Silver Star refinery and resigned in February 1885 once the work was complete.

[23] Frasch then joined John Minhinnick in forming a separate venture called the Empire Oil Company.

[22] The pair purchased an idle refinery in London, and Frasch began experimenting on a way to remove the sulphur content in the oil pumped at Lambton County.

[24] Between 1885 and 1887, Frasch discovered that mixing copper oxide with the oil during the distilling process would remove the sulphur content and odour from the refined product.

[26] After returning to the United States, Frasch perfected his desulphurization strategy, and Standard Oil held a monopoly on the process until 1905.

[33][34] Following the deal, Imperial Oil shut down the Silver Star refinery in Petrolia and moved its refining operations to Sarnia, Ontario.

[33] In a landmark 1911 anti-trust case, the U.S. Supreme Court ordered Standard Oil to break up into 34 separate companies.

With ExxonMobil having majority ownership, Imperial Oil licences its parent company's brands, including the Esso and Mobil names for service stations, and the Speedpass electronic payment system.

On March 13, 2018, Loblaw Companies announced that it had reached a deal for the Esso-branded stations to join the PC Optimum rewards program, beginning on June 1, 2018.