This chapter in the Oxford Handbook of AI Governance synthesizes and discusses research on public opinion toward artificial intelligence (AI). Understanding citizens' and consumers' attitudes toward AI is important from a normative standpoint because the public is a major stakeholder in shaping the future of the technology and should have a voice in policy discussions. Furthermore, the research could help us anticipate future political and consumer behavior. Survey data worldwide show that the public is increasingly aware of AI; however, they -- unlike AI researchers -- tend to anthropomorphize AI. Demographic differences correlate with trust in AI in the abstract: those living in East Asia have higher levels of trust in AI, while women and those of lower socioeconomic status across different regions have lower levels of trust. Surveys that focus on particular AI applications, including facial recognition technology, personalization algorithms, lethal autonomous weapons, and workplace automation, add complexity to this research topic. I conclude this chapter by recommending four new topics for future studies: 1) institutional trust in actors building and deploying AI systems, 2) the impact of knowledge and experience on attitudes toward AI, 3) heterogeneity in attitudes toward AI, and 4) the relationship between attitudes and behavior.