The Strait of Dover or Dover Strait (French: Pas de Calais French pronunciation: ​[pɑ d(ə) kalɛ] - Strait of Calais), is the strait at the narrowest part of the English Channel, marking the boundary between the Channel and the North Sea, separating Great Britain from continental Europe. The shortest distance across the strait, at approximately 20 miles (32 kilometres), is from the South Foreland, northeast of Dover in the English county of Kent, to Cap Gris Nez, a cape near to Calais in the French département of Pas-de-Calais. Between these points lies the most popular route for cross-channel swimmers. The entire strait is within the territorial waters of France and the United Kingdom, but a right of transit passage under the United Nations Convention on the Law of the Sea allows vessels of other nations to move freely through the strait.

On a clear day, it is possible to see the opposite coastline of England from France and vice versa with the naked eye, with the most famous and obvious sight being the White Cliffs of Dover from the French coastline and shoreline buildings on both coastlines, as well as lights on either coastline at night, as in Matthew Arnold's poem "Dover Beach".