Her Majesty's Government (or His Majesty's Government) is the formal mode of address given to a government in a kingdom where executive authority is vested in the monarch and exercised in theory on his or her behalf by his/her government, hence the term.

Her Majesty's Government is particularly associated with the United Kingdom and is used in particular in diplomatic and foreign relations. It is also associated with many Commonwealth Realms which share the same person as monarch as the United Kingdom. In the 1920s, the Irish Free State, to stress its equality with the United Kingdom, referred to itself as His Majesty's Government in the Irish Free State, and to the King's Government in the United Kingdom as His Majesty's Government in the United Kingdom.

The Labour government under Tony Blair has opted not to use the phrase except in formal documentation.