According to a Foundation statement on Wednesday, veteran Australian broadcaster Mary Kostakidis praised WikLeaks as an "ingenious and heroic website that has shifted the power balance between citizen and the state by exposing what governments really get up to in out name".
Acknowledging that "exposing secrets can be dangerous business", Kostakidis thanked Assange for his "heroic courage" as a whistleblower to take "great risks for our benefit".
In accepting the Gold Medal, Assange 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," he said.
Although the Peace Prize is awarded annually by the foundation only three other people in its 14-year history have been awarded the gold award for courage in pursuit of human rights, the Dalai Lama, Nelson Mandela and Japanese Buddhist leader Daisaku Ikeda.
Whistleblowing website, WikiLeaks founded by Assange published thousands of cables in which US diplomats gave their often candid views on world leaders, to Washington's acute embarrassment.