Significance: The implementation of social-distancing measures to contain the COVID-19 pandemic has disrupted daily life activities, including smoking-related practices in smokers. We examined the associations of changes in smoking-related practices with smoking reduction and quit attempts since the outbreak. Methods: Data were collected from 659 current smokers who responded to a telephone survey conducted from May to June 2020 in Hong Kong. During this period, the Hong Kong government has implemented social-distancing restrictions but no lockdown. Participants reported if they have reduced their smoking consumption, made a quit attempt, and changed several smoking-related practices since the COVID-19 outbreak. We estimated the prevalence ratio (PR) of smoking reduction and quit attempts in relation to changes in the smoking-related practices, adjusting for sex, age, education, chronic disease status, heaviness of smoking, and perceived risk of COVID-19 and mutual adjustment. Results: Since the outbreak, 26.2% of the participants had reduced smoking and 17.9% made a quit attempt; 60.4% reported having avoided smoking on the street, 51.7% avoided smoking with other smokers, 34.3% reduced going out to buy cigarettes, 25.4% increased smoking at home, and 20.0% stockpiled tobacco products. Multivariable models showed that having reduced going out to buy cigarettes was significantly associated with smoking reduction (PR 2.67; 95% CI 1.93-3.68; P<0.001); having avoided smoking on the street (PR 1.93; 95% CI 1.20-3.10; P<0.006) and reduced going out to buy cigarettes (PR 1.97; 95% CI 1.36-2.86; P0.05). Conclusion: Many participants reported changes in their smoking-related practices since the COVID-19 outbreak; some changes were associated with smoking reduction and quit attempt, suggesting the outbreak to be an opportune time to promote smoking cessation.