A writ of election is a formal written order instructing the holding of an election. In Commonwealth countries, writs are the usual mechanism by which general elections are called and are issued by the head of state or their representative. In the United States, writs are more commonly used to call special elections for political offices. In Canada, a writ is the only way of holding an election for the House of Commons. When the government wants to or is required to dissolve Parliament, a writ of election is drawn up for each riding (electoral district) in Canada by the chief electoral officer and is formally issued by the governor general. Similarly, where a single riding becomes vacant, a writ is issued to trigger the by-election for that seat.

The writ specifies the day by which the names of candidates must be entered into nomination, sets a polling date, and sets a date on which the writ, with the name of the successful candidate noted on the back, is to be returned to the Chief Electoral Officer. The writs go through a formal process with several steps, some of which are prescribed in law, while others are governed by convention and tradition. The writs are printed by the electoral commission and thoroughly reviewed for accuracy. Each writ must contain key election dates and be inscribed with the names of the electoral district and the returning officer and his or her city of residence. The writs are then sent by priority post to the corresponding returning officers who keep them in a secure location for the duration of the election period.