The 2007 Labour Party Leadership Election was formally triggered on 10 May 2007 by the resignation of Tony Blair, Labour Leader since 21 July 1994. At the same time Blair resigned, John Prescott resigned as Deputy Leader triggering a concurrent election for the deputy leadership.

Informal campaigning had been ongoing ever since Tony Blair's original announcement in 2004 that he would not be fighting a fourth General Election as leader. Pressure for a timetable eventually led him to announce on 7 September 2006 that he would step down within a year. Labour's National Executive Committee (NEC) met on 13 May 2007 to decide a timetable. Nominations opened on 14 May and closed at 12:30 UTC+1 on 17 May 2007.

Blair said he expected Gordon Brown to succeed him, and that Brown 'would make an excellent Prime Minister'. When nominations for the leadership elections opened, Blair was one of those nominating Brown. From the start most observers considered Brown the overwhelming favourite to succeed Blair; John McDonnell, his only challenger, failed to secure enough nominations in order to get onto the ballot and conceded defeat to Gordon Brown.

The election process concluded with Gordon Brown being declared leader at a special conference on 24 June 2007. On 27 June, Tony Blair resigned as Prime Minister of the United Kingdom, and was succeeded as Prime Minister by Gordon Brown.