The coronavirus disease (COVID-19) pandemic has had profound consequences on collective mental health and well-being, and yet, older adults appear better off than younger adults. The current study examined mental health impacts of the pandemic across adult age groups in a large sample (n = 5,320) of Canadians using multiple hierarchical regression analyses. Results suggest older adults are experiencing better mental health and more social connectedness relative to younger adults. Loneliness predicted negative mental health outcomes across all age groups, while the negative association between social support and mental health was only significant at average and high levels of loneliness in the 65–69 age group. Results point towards differential mental health impacts of the pandemic across adult age groups and indicate that loneliness and social support may be key intervention targets during the COVID-19 pandemic. Future research should further examine mechanisms of resiliency among older Canadian adults during the pandemic.