The deputy mayor of Toronto is a member of Toronto City Council appointed to assist the mayor of Toronto. One councillor is designated for statutory purposes and additional deputy mayors may be appointed to represent the mayor on an honorary basis, but with no statutory authority.

Ausma Malik has served as the statutory deputy mayor since her appointment by Mayor Olivia Chow on August 10, 2023. Chow has named three additional deputy mayors: Paul Ainslie (Scarborough), Amber Morley (Etobicoke), and Michael Colle (North York).

The member designated for statutory purposes is sometimes known as the first deputy mayor. This councillor performs the roles and functions assigned to the "deputy mayor" in the City of Toronto Act and various chapters of the Toronto Municipal Code. The statutory deputy mayor has all the rights, power and authority of the mayor created by council, and is the vice-chair of the executive committee. The statutory deputy mayor typically acts when the mayor is unable to.

When the office of Mayor of Toronto is vacant, the deputy mayor exercises the limited mayoral powers which are granted to the mayor by city council to ensure city business can continue to be carried out. This includes acting as the city's chief executive officer, representing the city, and special privileges during council sessions. The deputy mayor also assumes responsibility for the administrative management of the mayor's office.

The deputy mayor does not become "acting" or "interim" mayor, nor does the deputy mayor assume the "strong-mayor" powers, which are granted by the province to the head of council, a role which remains vacant.

Non-statutory deputy mayors could be appointed to serve ceremonial roles. While holding no statutory authority, they represent the mayor at local events, can act as advisors, or lead a policy file. Additional deputy mayors were appointed under mayors David Miller, John Tory and Olivia Chow.