This mixed-methods complementarity study explored family members’, friends’, and health care providers’ perspectives of acceptability of group leisure activities as an intervention for loneliness experienced by older adults living with dementia. A sample of 25 family members, friends, and health care providers of people living with dementia in ON rated the acceptability of group leisure activities (adapted Treatment Perception and Preference questionnaire) and discussed their ratings in an interview. Quantitative (descriptive statistics) and qualitative (conventional content analysis) results were integrated to understand acceptability. Participants viewed group leisure activities as effective, logical, and suitable for use with people living with dementia. Participants described the need for flexible programs, careful facilitation, and attention to activity selection. Group leisure activities were seen as low risk, but stigmas related to dementia could prevent participation. The findings inform the design of acceptable group leisure activities, promoting their use to address loneliness in people living with dementia.