ABSTRACT Exposure to greenspace is protective of physical and mental health, but its role during the COVID-19 pandemic is unclear. We examined cross-sectional associations of residential greenness with behavioural, physical, and mental health outcomes during the fifth wave of COVID-19 in Hong Kong. A questionnaire of n = 160 participants assessed frequency of greenspace visits, physical activity from the International Physical Activity Questionnaire, and physical and mental health based on the 12-item Short-Form Health Survey. Residential greenspace was measured in terms of number of greenspace within a 400-m buffer, proximity to greenspace, and Landsat-derived Normalised Difference Vegetation Index as a metric of quality. Residing in higher greenness tertiles within 400 m was associated with higher odds of at least weekly visits to greenspace (OR = 3.23, 95% CI: 1.20-8.69 for the middle and OR = 5.62; 95% CI: 2.08-15.21 for highest tertiles) relative to the lowest exposure tertile. The count of residential greenspace was protectively associated with physical and mental health outcomes. The beneficial association between greenness and weekly usage remained robust at 500 m and was significant only among private housing residents. Policies towards scaling up and optimising residential greenness may constitute important public health interventions for enhancing population-level health and resilience during societal shocks