The mayor of Toronto is the head of Toronto City Council and chief executive officer of the municipal government. The mayor is elected alongside city council every four years on the fourth Monday of October; there are no term limits. While in office, mayors are styled His/Her Worship.

Olivia Chow has served as the 66th and current mayor of Toronto since July 12, 2023, after winning the 2023 by-election.

The role and powers of the mayor of Toronto are set out in the 1997 City of Toronto Act, an Ontario statute, and its update in 2006. It outlines the mayor's role as head of council and chief executive officer of the City of Toronto. In September 2022, the province passed legislation known as the Strong Mayors, Building More Homes Act, 2022, followed by the Better Municipal Governance Act, 2022, both of which expanded the executive power of the mayor.

As head of council, the mayor is responsible for ensuring business is carried out efficiently during council meetings. This has been delegated to the speaker of Toronto City Council, however, the mayor retains the ability to take over as chair during council meetings. Items can be added by the mayor directly to city council's agenda without going through a committee. Additionally, the mayor also holds ex officio membership on all council committees, chairs the Executive Committee, Striking Committee and the Civic Appointments Committee. The mayor has the power to appoint the chairs of other city committees as well as the deputy mayor. With the consent of the mayor, another member of council may take the mayor's place on committees. The head of council is also responsible for declaring states of emergency in the city.

Before the passage of the Strong Mayors Act, Toronto's government operated on what has been described as a "weak-mayor" system where all powers were vested in Council as a whole. In order to advance policy objectives, the mayor had to act as a consensus builder. The Strong Mayors Act shifted Toronto's government structure into one which resembles a "strong-mayor" system, assigning several administrative powers to the mayor which were previously held by City Council or an officer of the city.

The Strong Mayors Act expands the mayor's role in managing City Council's committee system and the overall organization of the city. Much of the work of the council is done in committees. The mayor sets out this structure by creating and dissolving committees, appoints their chairs and vice-chairs (this is a power that was delegated by council before 2022), and assigning their functions. Without the need for a motion by council, city staff can also be directed by the mayor to produce reports, develop policy and provide advice for city council to consider.

The mayor is also responsible for determining the organizational structure of the city. This includes the ability to create or dissolve city divisions, and appoint or terminate executive staff such as the city manager (who is the chief administrative officer) and the heads of city divisions.

Developing the annual budget of the City of Toronto is another key function of the mayor. Previously, the power to set the budget was a function of city council, which was assigned to the Budget Committee, allowing the mayor to exercise significant influence on the budget process. The power to draft the annual city budget is now assigned to the mayor. The mayor proposes the budget to council, which can adopt it or propose amendments.