To (i) assess how and to what extent online communities are used among breast cancer survivors (BCS) as a source of social support, (ii) describe the kind of support BCS access through online communities, and (iii) explore how these communities foster social support for BCS that promotes well-being and reduces the challenges of survivorship. We conducted a scoping review. A professional librarian performed a comprehensive search in multiple databases from January 2010 to May 2023. The review process adhered to the Johana Briggs Institute's method guidelines and the PRISMA-ScR reporting system. Fifteen studies were included. Participants used social media, cancer support communities, message boards, or websites for information and emotional support. Qualitative findings resulted in four themes: to reassure; to empower; to promote equity, diversity, and inclusion; and to demonstrate for BCS the drawbacks of online support. We underscore that a variety of internet websites and social media platforms are valuable for and appreciated by BCS, especially as a source of social support and human connectedness. Our study raises the existing gap in cultural/ethnic representation in this field and shows that institutional and organizational efforts are needed to address gaps in information regarding access to social support for multiethnic BCS women. This data synthesis will empower the BCS community by sharing how they can strengthen and support their peers and community via their participation in online communities that connect and support cancer survivors in healthcare spaces.