This introduction to the special issue on ‘Theorising life transitions: geographical perspectives’ makes the case for a greater focus on life transitions in geographical and social research on the life course. Echoing recent calls for a relational understanding of age, it discusses why and how ‘transition’ needs to be reconceptualised, however, to better capture the precariousness, unpredictability and diversity of life courses without ignoring the structuring effects of state regulation and the institutionalisation of life courses. The paper argues that geographical research has much to contribute to such a reconceptualisation, i.e. by showing the interconnections between social, spatial and life changes and by developing innovative methodologies to capture life transitions in their plurality.