The oil company will provide fuel for vehicles involved in the competition, as well as washing and catering facilities during the games.
In the four-year run up to the 2012 Olympics it will run exhibitions and cultural events as part of the 'Cultural Olympiad' programme run by the London Organising Committee of the Olympic Games.
With the addition of BP, LOCOG now has six top-tier partners including Lloyds TSB, EDF Energy, Adidas, British Airways and BT. Deloitte, the financial giant, is the only 'tier two' sponsor signed to date.
Sebastian Coe, the chairman of LOCOG, said: "BP has a well established track record of supporting the expertise and passion of our creative and cultural industries, and I hope that we will be able to draw upon it for our four-year cultural programme, which aims to inextricably link sport, culture, community and education."