The COVID-19 lockdowns had negative impacts on psychological well-being and amplified certain stressors (e.g., social isolation), especially in at-risk populations. My thesis examined social support availability as a coping strategy. Single people living alone (N=220) were recruited during the initial 2020 lockdown and followed over a period of six weeks. Each week, participants reported their perceived social support availability, social isolation, and life satisfaction. I hypothesized that greater perceptions of social support availability, both on the within- and between-person levels, would buffer the negative effects of social isolation on psychological well-being. Multi-level modeling results showed that stress-buffering occurred on the between-person level. Associations were analyzed longitudinally, revealing that lagged social isolation did not predict life satisfaction the week after. An interaction was observed between lagged social isolation and lagged social support availability, such that lagged social isolation predicted less life satisfaction when social support was unavailable the week before.