This article undertakes a comprehensive review of the Canadian law of force majeure and its application in the energy sector. The article begins by examining the legal foundations of force majeure found in the common law, Canadian jurisprudence, and other legal regimes. It then describes the operation of a force majeure clause and analyzes how such a clause is likely to be interpreted by the courts. The authors incorporate many practical suggestions that will be useful to drafters of force majeure clauses. Published in the Alberta Law Review, Energy Law Edition, Volume 49, No.2.