Screenwriter Richard Curtis has won a $25,000 (£14,000) prize for The Girl in the Cafe, his TV film set against the backdrop of a G8 summit.
The film explores the issue of world poverty in a romantic comedy
Curtis was one of a number of writers honoured at the annual Humanitas Prize awards, which recognise work that helps "liberate, enrich and unify society".
The Girl in the Cafe, starring Bill Nighy, was made as part of a range of BBC programmes celebrating Africa.
Paul Haggis and Bobby Moresco also won a $25,000 award for the film Crash.
The Humanitas judges commended the Oscar award-winning ensemble movie "for its call to reach out with respect and compassion to all of our brothers and sisters".
The awards honour mainly fictional work but a documentary by former US vice president Al Gore about global warming, An Inconvenient Truth, was given a special prize.
The judging panel is made up of over 50 screenwriters and other film industry professionals.
Other winners included Richard Glatzer and Wash Westmoreland's film Quinceanera, which follows a 14-year-old Hispanic girl in a Los Angeles neighbourhood as she prepares for her coming-of-age ceremony.
The film scooped the jury and audience best dramatic film honours at this year's Sundance film festival.
Greg Garcia won $10,000 (£5,500) for his pilot episode of US TV show My Name is Earl, a comedy about a small-time crook who tries to get back on the straight and narrow.