Background: Australia has mounted an effective response to HIV and AIDS by investing in evidence-informed policy. Recently, in response to increases in HIV in some states in Australia, the New South Wales Department of Health set up a ‘think tank’ to examine differences in epidemiological and behavioural data, policies, strategies and community responses in order to account for state-based differences and ensure an effective ongoing response to HIV. Methods: The National Centre in HIV Social Research undertook key informant interviews with major stakeholders to help understand differences in responses by the three states most affected by HIV in Australia – Queensland, New South Wales and Victoria. In parallel, the Australian Federation of AIDS Organisations completed an analysis of the investments in HIV-prevention activities targeting gay men in all jurisdictions in Australia. The Australian Federation of AIDS Organisations also analysed the strategic contexts and government responses to HIV in the three states. Results: There were significant differences between New South Wales, Queensland and Victoria in the way the HIV partnership functions. Type of prevention strategy and level of financial investment in prevention activities appear to be related to the effectiveness of the ongoing response to HIV. Conclusions: An active commitment to and adequate resourcing of HIV prevention by all stakeholders in the HIV partnership – government and non-government departments, researchers and gay community organisations – is crucial if Australia is to respond effectively to HIV among gay and other men who have sex with men.