Loneliness is unequally experienced among older populations, reflecting structural inequalities across multiple life domains. However, research on loneliness in later life has disproportionately focused on individual characteristics (e.g., physical health, mental health, personality traits), often overlooking structural inequalities in access to opportunities and resources—inequalities that are frequently linked to discrimination and social exclusion. This chapter aims to enhance understanding of the interrelation between loneliness and social exclusion by applying a multidimensional framework that connects exclusion in various life domains to loneliness in later life. Specifically, we examine five key dimensions of old-age social exclusion: economic, social, service-related, community/spatial, and civic exclusion. We analyse empirical evidence demonstrating how exclusionary processes at the individual, community, and societal levels contribute to loneliness, highlighting that loneliness is not merely a personal experience, but a broader issue shaped by multidimensional and societal mechanisms. By framing social exclusion as both a theoretical lens and a practical tool, this chapter contributes to the growing field of integrated loneliness research. Our discussion underscores the need for multilevel interventions that address not only personal risk factors but also the structural determinants of loneliness in later life.