The 2009 G-20 London Summit is the second meeting of the G-20 heads of state in discussion of financial markets and the world economy, which was held in London on 2 April 2009 at the ExCeL Exhibition Centre. It followed the first G-20 Leaders Summit on Financial Markets and the World Economy, which was held in Washington, D.C. on 14–15 November 2008. Heads of government or heads of state from the Group of Twenty Finance Ministers and Central Bank Governors (G-20), plus some regional and international organisations attended. Due to the extended membership it has been referred to as the London Summit.

The policing tactics at the event raised some controversy, particularly over the death of Ian Tomlinson.