Among the guests were US First Lady Michelle Obama, UN Secretary-General Ban Ki-moon, Russian Prime Minister Dmitry Medvedev and IOC President Jacques Rogge.
Her Majesty said: "In all our Olympic teams there is so much of which we can be proud of. Groups of young men and women dedicated to excellence and achievement across numerous sporting disciplines.
"And these teams are ably supported by thousands of organisers, volunteers and supporters who will be following the actions not just at the Olympic venues here in the United Kingdom but throughout the world.
"For all these reasons I wish you and your countries successful, enjoyable and memorable games," said the Queen
Later in the evening, the Royals and their guests were due to travel to Stratford for the opening ceremony of the 2012 Olympics.
