Aim The study aims to project future trends in living arrangements and access to children's cash contributions and market income sources among older people in Hong Kong. Method A cell‐based model was constructed by combining available population projections, labour force projections, an extrapolation of the historical trend in living arrangements based on national survey datasets and a regression model on income sources. Results Under certain assumptions, the proportion of older people living with their children may decline from 59 to 48% during 2006–2030. Although access to market income sources may improve slightly, up to 20% of older people may have no access to either children's financial support or market income sources, and will not live with their children by 2030. Conclusion Family support is expected to contract in the next two decades. Public pensions should be expanded to protect financially vulnerable older people.