The Rideau Canal (French: Canal Rideau), also known as the Rideau Waterway, connects the city of Ottawa, Ontario, Canada on the Ottawa River to the city of Kingston, Ontario on Lake Ontario. The canal was opened in 1832 as a precaution in case of war with the United States and is still in use today, with most of its original structures intact. The canal system uses sections of major rivers, including the Rideau and the Cataraqui, as well as some lakes. It is the oldest continuously operated canal system in North America, and in 2007, it was registered as a UNESCO World Heritage Site.

It is operated today by Parks Canada as a recreational waterway. The locks on the system open for navigation in mid-May and close in mid-October.

In winter, a section of the Rideau Canal passing through central Ottawa becomes officially the world's largest skating rink. The cleared length is 7.8 kilometres (4.8 miles) and has the equivalent surface area of 90 Olympic hockey rinks. It runs from the Hartwell locks at Carleton University to the locks between the Parliament Buildings and the Ch?teau Laurier, including Dow's Lake in between. It serves as a popular tourist attraction and recreational area and is also the focus of the Winterlude festival in Ottawa. Beaver Tails, a fried dough pastry, are sold along with other snacks and beverages, in kiosks on the skateway. In January 2008, Winnipeg, Manitoba achieved the record of the world's longest skating rink at a length of 8.54 kilometres, but with a width of only 2 to 3 metres wide, on its Assiniboine River and Red River at The Forks. In response, the Rideau Canal was rebranded as "the world's largest skating rink".