Greening Australia is an Australian environmental organisation, founded in 1982, the International Year of the Tree, to protect, restore and conserve Australia's native vegetation. Greening Australia was formed by the United Nations Association of Australia and the Nursery Industry Association of Australia.

In the 1980s tree cover decline was acknowledged as having a serious adverse impact on agricultural and pastoral productivity. Removal of tree cover was also linked with the development of salinity, soil degradation and erosion, and declining water quality. On World Environment Day in 1982, then Prime Minister Malcolm Fraser announced the establishment of the National Tree Program, which aimed to reverse tree decline throughout Australia. Greening Australia provided the non-government arm of the National Tree Program. With representation in every state and territory and a national office in Canberra, Greening Australia became the primary focus for non-government tree projects.

Since its inception, Greening Australia has undergone a natural evolution – from a focus on trees to a focus on landscape. The Gondwana Link and River Recovery projects reflect this change and the need to address the impacts of climate change.

Greening Australia has been involved in many large scale revegetation and restoration projects in Australia since its inception, including the National Tree Program, the One Billion Trees Project, Bushcare Support, National Corrdiors of Green, Florabank and Green Corps. The focus of its work lies in providing trees and tree planting services, technical advice and education, volunteer co-ordination and funding for restoration projects.

On World Environment Day 1998, Greening Australia's work was recognised with admission to the United Nations Environment Programme Global 500 Roll of Honour. This award recognises outstanding achievements in protection of the environment, and represents a significant achievement for Australia's role in world conservation.