Australia has a significant private rental market with over a quarter of households renting their home from a private landlord. Many of these households are on low incomes and receive assistance from private rental support programs provided by each Australian state and territory. In spite of these large numbers, little is known about the effectiveness of policy initiatives to assist low-income private renters. Limited knowledge of the private rental support programs stands in stark contrast to the detailed research on programs established to address homelessness and problems within the public housing sector. This paper addresses this lacuna by reporting on the suite of initiatives currently funded by state governments to assist low-income households (for example, bond loans and rental deposits, advice and help with removal expenses). Based on a comprehensive study of Private Rental Support Programs (PRSPs) commissioned by the Australian Housing and Urban Research Institute, it is argued that though policies to assist vulnerable tenants are acknowledged as a success by practitioners and clients, their effectiveness as a policy instrument is undermined by wider structural changes in the housing market. The paper concludes that the stress faced by many vulnerable households is likely to intensify over the coming years thereby compounding the pressure on state Housing Authorities to provide more comprehensive packages of support that extend beyond just a ‘one-off’ form of assistance.