Social identification has a wide variety of benefits for individual and public health. However, research is only just beginning to design and evaluate interventions that directly target social identification. In this project, we partnered with a community organisation (Relationships Australia) to evaluate a whole-of-community intervention called Neighbour Day, in which the whole nation is encouraged to reach out and build social connectedness in their local neighbourhood. In 2019, participants were 437 hosts of Neighbour Day events held across 344 diverse suburbs. Participants were surveyed before and after Neighbour Day, as well as at six-month follow up. Hosting a Neighbour Day event led to a significant increase in neighbourhood social identification which was sustained six months later. The project continues in 2020, with a focus on developing our understanding of how the science of social identity can be implemented in community settings to benefit public health.