The purpose of this study was to describe the social isolation of older adults in the Côte-des-Neiges neighbourhood (Montreal, Canada) from the perspectives of older adults and community stakeholders. To do so, a descriptive qualitative study was conducted, involving community-dwelling older adults and a variety of key stakeholders from the neighbourhood. Seven focus groups were held, with a total of 37 participants. Focus group transcripts were analyzed using the approach of Miles, Huberman, and Saldaña. Participants reported that social isolation of older adults is characterized by gaps in social interactions (scarcity of social interactions, lack of social support, and unsatisfying relationships) as well as by low social participation that can be depicted in three ways: (1) exclusion by society, (2) self-restriction of participation, and (3) low eagerness to socialize. This study highlights that there is a diversity in how social isolation of older adults manifests itself. It can be the result of a deliberate choice (or not), as well as being desired (or not). These aspects of the phenomenon of social isolation of older adults are still not well described. However, they offer relevant avenues for rethinking approaches to intervention development.