Financial barriers and limited cooking facilities are major obstacles to healthy dietary practices among the homeless population. Homelessness is currently at crisis point and up-to-date evidence from multiple stakeholders is needed to address dietary inequalities. The aim of this study was to understand dietary practices, barriers to healthy eating within homeless services from multiple perspectives. Twelve service users and five healthcare and social service providers participated in semi-structured interviews. Data were analysed thematically. Four themes were identified which included: lack of control over diet and food supply; sources of food for the homeless population; practical barriers to good nutrition; and the impact of diet on emotional and physical wellbeing. Frequent consumption of energy-dense, nutrient-poor foods was reported. Food insecurity resulted in perceived depressive symptoms and stress. Barriers to healthy diet included financial constraints and a lack of access to cooking and storage facilities. Our study highlights low levels of food skills and healthy eating knowledge among service users and service providers. In order to address diet-related health disparities, health promotion initiatives should be targeted at building healthy public policy in relation to diet and nutrition and developing food skills with members of this population and service providers.