Later-life loneliness is a growing public health concern, resulting from a lack of desired social relationships. Despite evidence suggesting that social and residential mobility affect older adults' social ties and sense of belonging, their impact on later-life loneliness remains unexplored. This project aims to fill this gap by examining their effects from a life course and cross-national comparative perspective. It argues that older adults’ own as well as their children’s social and residential mobility throughout the life course may influence feelings of loneliness in later life. Furthermore, the study assumes that the impact of mobility processes depends on when they occurred throughout the life span and can be mitigated by institutional policies and neighborhood conditions that foster social cohesion. By using pooled data from three longitudinal ageing studies (ELSA, HRS and SHARE), this project will relate later-life loneliness to the core sociological theme of mobility.