Abstract Background The COVID-19 pandemic has forced countries to take various restrictive measures, including “lockdowns”, which may have affected tobacco smoking. The study explored associations between an increase in smoking, sociodemographic, and related to pandemic factors during pandemic among social media users in Russia. Methods Between June-September 2020, 1518 users of the most popular in Russia social media networks participated in online survey investigating changes in alcohol, tobacco, and substance use during pandemic. Binary logistic regression was used to identify factors associated with an increase in tobacco smoking. The analysis was adjusted for sex, level of education, perception of the severity of public life restrictions, negative work/financial consequences of the pandemic, stress, changes in the frequency of drinking, heavy episodic drinking (6 or more standard drinks at a time), and the volume of alcohol consumed on a typical occasion. Results 46.8% of the surveyed population were current smokers. 17.0% of them reduced, 37.9% increased, and 45.1% didn’t change their smoking during the pandemic. Relative to those whose smoking reduced or didn’t change, those who increased their smoking were more likely to be: 18-29 years old (OR = 1.906; 95% CI = 1.109-3.277), residents of medium to big cities (up to 1 mln inhabitants) (1.519; 1.017-2.270), had their income reduced (1.508; 1.024-2.222), faced severe restrictions in everyday life as a result of measures taken to contain SARS-CoV-2 (2.398; 1.440-3.758). After introducing alcohol consumption variables to the model, only two factors were associated with an increase in smoking: severe restrictions in everyday life (2.147; 1.227-3.993) and increased frequency of heavy episodic drinking during pandemic (2.338; 1.167-4.685). Conclusions Increase in tobacco smoking during pandemic was associated with severe restrictions in everyday life and increased frequency of heavy episodic drinking among social media users in Russia. Key messages • More than a third of social media users increased tobacco smoking during pandemic, which was associated with severe restrictions in everyday life and increased frequency of heavy episodic drinking. • During pandemics and similar public health crises, it is advisable to expand remote counseling services for alcohol and tobacco cessation, which can be delivered through social media.