Objective: Food insecurity is an increasing problem in marginalised groups that affects diet quality. We aimed to examine the extent of food insecurity and the eating patterns of young people accessing support from specialist homelessness services. Methods: A cross-sectional survey with a researcher-administered food frequency and food insecurity questionnaire was undertaken with 50 young people experiencing homelessness, aged 14-26 years. Participants were recruited from 11 specialist homelessness services providing support and accommodation for young people in central and south-western Sydney. Results: Food insecurity was a recent experience for 70% of participants. Eighty-five per cent of participants living independently experienced food insecurity, compared to 66% of young people in supported accommodation. Consumption of core food groups was low, as almost all participants did not meet recommended daily servings of vegetables and breads and cereals. Consumption of sugar-sweetened soft drinks was high. Conclusions: Food insecurity and poor diet quality are salient issues for this group of young people accessing support from specialist homelessness services. Implications: These findings highlight the need for a greater focus on advocacy and policy action to increase social supports and improve food security and nutrition for young people experiencing homelessness.