Governments around the world are adopting facial recognition technology (FRT) to improve public services and law enforcement. Past research has shown that such applications may result in discriminatory effects and threaten privacy. This study shines light on the question of what drives public opinion regarding FRT in different socio-political contexts. Based on an online survey and semi-structured interviews, this study finds that citizens in China, Germany, the United Kingdom, and the United States differ in their acceptance of the official public use of FRT. China has the highest approval rates, Germany and the US have the lowest, and the UK lies in the middle. Our results show that people are generally more willing to accept FRT in public spheres when they trust government institutions, believe the technology should be managed by the central government, and have an affinity for technology. People's awareness of a country's previous history of surveillance further shapes their perceptions of FRT. Across all four countries, we also show that privacy concerns, especially of FRT compromising one's privacy, have the biggest influence on respondents' attitudes. Expanding on existing research into FRT acceptance and usage, our results suggest that policymakers urgently need to address the current regulatory vacuum.