Background: Research has identified that loneliness during COVID-19 is associated with co-residence status, and individuals living alone were more likely to report loneliness. However, it may not apply to sexual minority people as those living with their family may experience different sexual orientation-related stressors. Aims: This study aims to (1) understand the pattern of living arrangement and loneliness among sexual minority people during COVID-19, (2) examine parental acceptance, family conflict and loneliness among sexual minority people with different living arrangements and (3) investigate the association between parental acceptance and loneliness among sexual minority people with different living arrangements during COVID-19. Method: An online survey with 1,457 Hong Kong sexual minority people was conducted. Results: Sexual minority people living with their partner(s) were less likely to report loneliness. Concurrently, those living with their parent(s) showed a similar level of loneliness as those who lived alone. Living with parent(s) during COVID-19 does not necessarily alleviate feelings of loneliness among them, which we argue may be due to parental unacceptance of their sexual orientation. Nearly half of the respondents stated that their parent(s) were unaccepting of their sexual orientation and 41.8% of them indicated an increase in family conflict during COVID-19. For those living with their parent(s), parental unacceptance is related to more family conflict during COVID-19, which in turn is associated with higher levels of loneliness. Conclusions: Not living with unaccepting parents may reduce family conflict and feelings of loneliness, but this has not been the case for many respondents from a city with high population density and cost of living. Social and mental health service providers need to come up with timely and appropriate interventions to address the unique needs faced by sexual minority people during and after the COVID-19 pandemic.