Festival director Marco Mueller said the lighter Hollywood presence was partly due to disruptions caused by a 14-week writers' strike that ended in February, meaning the release of some films had to be postponed.
"Some of the films which would have normally been ready in time for Venice now won't be released until December or later," Mueller told a news conference, unveiling the programme of the festival's 65th edition.
Last year, U.S. and British films dominated the lineup, with nearly half of the films in the main competition.
This year, only five English-language movies - all listed as U.S. productions - will vie for the top prize at the world's oldest film festival.
Among them is Jonathan Demme's "Rachel Getting Married", starring Anne Hathaway and Debra Winger in the story of a woman returning home for her sister's wedding after spending 10 years in and out of rehabilitation centres.
The other U.S. films in the main contest, all by lesser-known or first-time directors, include "The Burning Plain" - a family drama with Kim Basinger and Charlize Theron - and "The Wrestler", with Mickey Rourke in the lead role.
Italy and Japan loom large over the rest of the 21-film competition, with four and three movies respectively. Two of the Japanese offerings are animation films, including "Ponyo on Cliff by the Sea" by cult director Hayao Miyazaki.
Outside competition, "Burn After Reading" by Oscar-winning directors Joel and Ethan Coen will open the 11-day movie marathon on Aug. 27.
The film, starring George Clooney and Brad Pitt, should bring to the Venice red carpet some of the Hollywood star power that is critical to the success of any festival.
Veteran film-makers Manoel de Oliveira, who turns 100 this year, and Mario Monicelli will present two short works at the festival, which traditionally combines obscure art house cinema with A-list celebrities.
For the second year running the unofficial prize for the longest film will go to Filipino director Lav Diaz, whose "Melancholia" runs for seven-and-a-half hours.