The Mayor of London is an elected politician who, along with the London Assembly of 25 members, is accountable for the strategic government of Greater London. Conservative Boris Johnson has held the position since 4 May 2008. The position was previously held by Ken Livingstone from the creation of the role on 4 May 2000 until his succession by Johnson.

The role, created in 2000 after the London devolution referendum, was the first directly elected mayor in the United Kingdom. The Mayor of London is also referred to as the London Mayor, a form which helps to avoid confusion with the Lord Mayor of the City of London, the ancient and now mainly ceremonial role in the geographically smaller central region of the ancient City of London. The Mayor of London is the mayor of the entirety of Greater London (including the City).