Loneliness is a growing public health concern that impacts individual's well-being. However, mechanisms that protect against the effects of loneliness have not been examined widely. Guided by prior literature documenting that loneliness and a sense of community are related, this study sought to test the mediating role of a sense of community on loneliness and well-being and the moderating role of gender. A sample of 2993 Korean adults completed an online survey regarding their sense of community, loneliness, and well-being. We conducted mediation and moderated mediation analyses. The mediation analysis revealed that sense of community mediates the relationship between loneliness and well-being suggesting that sense of community may be an important area for intervention. Analyses did not reveal gender differences in the relationship between loneliness and sense of community. The findings of this study may be important when considering the design of community-based interventions to address loneliness.