Behaviours play a key role in improving health and wellbeing.  Identifying and understanding behaviours and factors that influence them, and how best to address these factors is integral to achieving the ambitions of public health policy and practice. Many professionals across the public health system in Wales are striving to make an impact on population health using this type of behavioural science. Our October e-bulletin includes a range of projects and initiatives that are using behavioural science to improve the health and well-being of communities across Wales.