Background. Although the importance of social media platforms in people’s daily lives and their role in advertisement, and the persistent increase in online gambling participation over the years are unquestioned, no study has examined how the unavailability of social media affects online gambling. A 6-hour-long worldwide outage of Facebook on 4th October 2021 created a unique possibility to investigate this relationship. Objectives. The aim of the present study was to examine whether online gambling behaviour during the Facebook outage was different from gambling patterns on other Monday evenings. Methods. We analysed behavioural tracking data from an online gambling service provider, Fortuna Entertainment Group (FEG). The datasets included information on the gambling patterns of 232,037 players from five different countries (Croatia, Czechia, Poland, Romania, and Slovakia) on five consecutive Mondays, including the day of the Facebook outage. A linear regression was estimated for several outcome variables (number of players, amount of stake, number of bets) separately for each country and gaming and sports betting type of gambling, while gender, age, time, and date were included as control variables. Results. Most of the ordinary least squares (OLS) regressions showed a non-significant impact of the outage, and only a few significant, but small differences were identified. In these cases, the outage was associated with a lower outcome. Conclusion. In the case of the examined countries, the Facebook outage only had a marginal impact on gambling behaviour. Further research and analysis are needed to explore the connection between social media use and abstinence and gambling.