Lloyd Webber said Friday the games will make it "very tough" for shows in London's West End and predicted that three major musicals would not play over the games.
The composer told BBC radio that the biggest hits - such as his own "The Phantom of the Opera" - would play over the games but that others would struggle to draw crowds.
He says advance bookings for West End shows were running at only 10 percent of their normal level.
Lloyd Weber's Really Useful Group owns seven London theaters. Others in the industry have predicted a slump in demand over the summer.