Active ageing is a multidimensional concept referring to a situation where people continue to participate in the formal labour market, engage in unpaid productive activities (such as care provision to family members and volunteering), and live healthy, independent and secure lives as they age. Active ageing policies thus need to address this variety of dimensions: enable possibilities for longer working life, ensure social involvement, encourage healthy lifestyles, and provide opportunities for independent living for both men and women. Monitoring such policy implementation requires a comprehensive tool that encompasses the multitude of aspects of active ageing. The Active Ageing Index (AAI) is such a tool. It captures various facets of active ageing: it measures how much of older men and women’s potential to contribute to the economy and society is used and to what extent their living environment enables them. They contribute by working, volunteering, providing informal care, living independently, and staying healthy. AAI offers a flexible framework that can be applied to different countries and at national as well as subnational (regional and local) levels. It depicts the current situation and highlights the areas where future gains can be made. A country might have high results in one domain, for example employment, with relatively low results in another one, such as independent living. This signals that matters enabling independent living need particular attention.