Mr. Assange was given the Sydney Peace Medal at a ceremony at the Frontline Club in central London today.
The Sydney Peace Foundation said that it was making the award to recognise Mr in recognition of the need “for greater transparency and accountability of governments”.
Professor Stuart Rees, director of the foundation, said: “By challenging centuries old practices of government secrecy and by championing people’s right to know, WikiLeaks and Julian Assange have created the potential for a new order in journalism and in the free flow of information.”
Speaking at the event, Mr Assange referred to whistleblowers as "heroes" and said it appeared the website had played a "significant role" in the recent Arab uprisings in north Africa by releasing US diplomatic cables in December that were later translated into Arabic and French.
He said WikiLeaks was part of England's historic "free speech traditions, these go back in the UK to the time of the English Civil War of the 1640s". He said: “The real value of this award, and the Sydney Peace Foundation is that it makes explicit the link between peace and justice.
“It does not take the safe feel good option of shunning controversy by uttering platitudes. Instead it goes into difficult terrain by identifying organisations and individuals who are directly engaged in struggles of one kind or another.
“With WikiLeaks we are all engaged in a struggle, a generational struggle for a proposition that citizens have a right and a duty to scrutinise the state."
WikiLeaks has caused controversy over the past year by releasing secret US Government documents including reports about detainees held in Guantanamo Bay, Cuba and hundreds of thousands of US diplomatic cables.
Mr Assange is currently staying in Norfolk while he fights extradition to Sweden over allegations of sexual crimes, which he denies.