Aboriginal people and their culture have been the focus of much of Penny Tweedie's photography during the last period of her career. In 1975 she photographed Prime Minister Gough Whitlam handing back the land to Vincent Lingiari at Wattie Creek in the Northern Territory to celebrate the first successful Aboriginal land claim. In 1980, after several years living and working closely with Aboriginal families and communities in Arnhem Land, National Geographic magazine published her story on their enduring traditional culture and customs, which she followed with a book 'This is my Country: A View of Arnhem Land', in 1985. Tweedie's book, Spirit of Arnhem Land, was published to international acclaim, photographs from which won the Walkley award for feature photography in 1999. Tweedie worked on assignments for major magazines and publications including National Geographic, Newsweek, Time Magazine and the Sunday Times, and non-goverment organisations such as Save the Children and Oxfam. Assignments took the photographer to over sixty countries where she photographed war, famine, historical and political events, and people and the environment.