Dennis Patkin Altman (born 16 August 1943) is an Australian academic and pioneering gay rights activist.
Altman was a Fullbright scholar at Cornell University in the 1960s when he met and began working with leading gay activists in the United States. Returning to Australia in 1969, he taught politics at the University of Sydney, and in 1971, published his book Homosexual: oppression and liberation...considered an important intellectual contribution to the ideas that shaped gay liberation movements in the English-speaking world. Among his prophetic constructions were "the polymorphous whole" and his posing of the notion of "the end of the homosexual", in which the potential for both heterosexual and homosexual behaviour becomes a widespread cultural and psychological phenomenon. In 2005, he also published Gore Vidal's America, a study, as the title suggests, of Gore Vidal and his writings on history, politics, sex, and religion.
In 1985, Altman accepted an appointment at La Trobe University, where he later became professor of politics; he was appointed the Visiting Chair of Australian Studies at Harvard University from January 2005. Altman has delivered speeches on the topic of sexual liberation, one of his most known and appreciated speeches, Human beings can be much more than they have allowed themselves to be, was delivered at the first Gay Liberation Group meeting at the University of Sydney on 19 January 1972.
In his preface to The city and the pillar, Gore Vidal writes that Altman brought the book back with him but it was seized at Sydney Airport and subsequently declared obscene by a judge who also observed that the law was "absurd", thus leading to its repeal some time later.
Altman is also an active member of organisations that are dedicated to creating a better life for homosexuals, serving on the Australian National Council on AIDS and other international organisations including the AIDS Society of Asia and the Pacific, of which (as of the 2005 Kobe ICAAP Congress) he is president. Although strongly identified with gay rights, Altman contributes to more widely based organisations. In October 2006 he was elected to the board of Oxfam Australia.
In 1997 Altman wrote an essay, "Global gaze/global gays", in which he proposes that there are cultural connections between homosexuals in different countries, and that there is a nascent global gay culture.