The London Assembly election of 2012 was an election of members to the London Assembly which took place on Thursday, 3 May 2012, the same day as the 2012 London mayoral election, and the 2012 United Kingdom local elections. Although Conservative candidate Boris Johnson won the Mayoral election, the Assembly election produced the Labour Party's best result since the inception of the London Assembly; this was subsequently surpassed by the party's performance in the 2016 election.

The 2012 London mayoral election was an election held on Thursday 3 May 2012, to elect the Mayor of London. It was held on the same day as the London Assembly election, and used a supplementary vote system.