Purpose: Cancer threatens the social well-being of patients and their informal caregivers. Social life is even more profoundly affected in advanced diseases, but research on social consequences of advanced cancer is scarce. This study aims to explore social consequences of advanced cancer as experienced by patients and their informal caregivers.; Methods: Seven focus groups and seven in-depth semi-structured interviews with patients (n = 18) suffering from advanced cancer and their informal caregivers (n = 15) were conducted. Audiotapes were transcribed verbatim and open coded using a thematic analysis approach.; Results: Social consequences were categorized in three themes: "social engagement," "social identity," and "social network." Regarding social engagement, patients and informal caregivers said that they strive for normality by continuing their life as prior to the diagnosis, but experienced barriers in doing so. Regarding social identity, patients and informal caregivers reported feelings of social isolation. The social network became more transparent, and the value of social relations had increased since the diagnosis. Many experienced positive and negative shifts in the quantity and quality of their social relations.; Conclusions: Social consequences of advanced cancer are substantial. There appears to be a great risk of social isolation in which responses from social relations play an important role. Empowering patients and informal caregivers to discuss their experienced social consequences is beneficial. Creating awareness among healthcare professionals is essential as they provide social support and anticipate on social problems. Finally, educating social relations regarding the impact of advanced cancer and effective support methods may empower social support systems and reduce feelings of isolation.