Hailed by The New York Times as 'the Oscars of the internet', the Webbys receive worldwide media attention and are judged by a panel which includes Simpsons creator Matt Groening and movie mogul Harvey Weinstein.
"It is thrilling to have this recognition for what we do," said Struan Robertson, editor of OUT-LAW.COM. "It is even nicer that users have already been sending in their congratulations."
"OUT-LAW was quite an adventurous idea when it launched eight years ago and it remains an unusual one in the world of law firms. The site has been hugely popular but it is gratifying to have a Webby as independent recognition for what we do," he said.
Websites and mobile services compete in 100 categories and other winners this year included Yahoo!, Apple, the Financial Times, the BBC and The New York Times. There were almost 10,000 entries from more than 60 countries for the 12th Annual Webby Awards.
As well as being the first law firm winner, OUT-LAW was also the first ever nominee for 'Best law website' from a non-US organisation.
The other nominees shortlisted for 'best law website' were US firm Shearman & Sterling LLP, the American Bar Association (ABA) Journal, the University of Pittsburgh School of Law and Pro Bono Net. The ABA Journal won the voted-for People's Voice award in the law category.