Vaccination saves millions of lives, and the World Health Organization (WHO) European Region celebrated record high coverage in 2018. Still, national or sub-national coverage is insufficient to stop the spread of vaccine-preventable diseases. Health authorities are increasingly aware of the need to prioritize the “demand” side of vaccination. Achieving high and equitable vaccination uptake in all population groups is not a quick-fix; it requires long-term investment in multifaceted interventions, informed by research with the target groups. The WHO focuses on both individual and context determinants of vaccination behaviours. Individual determinants include risk perceptions, (dis)trust and perceived constraints; insights from psychology help us understand these. Context determinants include social norms, socioeconomic status and education level, and the way health systems are designed, operate and are financed. The WHO recommends using a proven theoretical model to understand vaccination behaviours and has adapted the “COM‑B model” for their Tailoring Immunization Programmes (TIP) approach. This adapted model is described in the article. Informed by insights into the factors affecting vaccination behaviours, interventions and policies can be planned to increase vaccination uptake. Some evidence exists on proven methods to do this. At the individual level, some interventions have been seen to increase vaccination uptake, and experimental studies have assessed how certain messages or actions affect vaccination perceptions. At the context level, there is more documentation for effective strategies, including those that focus on making vaccination the easy, convenient and default behaviour and that focus on the interaction between caregivers and health workers.