A significant number of Australians are employed in the road transport industry. Research identifies road transport industry workers, particularly truck drivers, as being at increased risk of chronic disease. In part, this is because truck drivers' working environment restricts their capacity to engage in physical activity and limits their access to healthy food options. Workplaces are now widely recognised as effective platforms for health promotion. Research suggests health promotion interventions in blue-collar workplaces can be effective in improving workers' health knowledge, behaviour and outcomes. However, truck drivers' workplaces are their vehicles, and so they are identified as a 'hard-to-reach' group for health promotion.This mixed-methods project implemented health promotion interventions in six road transport industry workplaces in Queensland, Australia. The project achieved improvements in key aspects of truck drivers' health knowledge, health behaviour and self-reported health outcomes. This was underpinned by positive changes in the healthrelated culture of participating workplaces. This project demonstrates Participatory Action Research (PAR) processes - including the development of robust relationships between the project team and workplace managers, changes in workplace culture and the effective contextualisation of interventions - can be successful in improving the health of this 'hard-to-reach' group.