This chapter discusses the concept of data governance in smart cities. There are legal considerations when using data, such as personal information protection law and the protection of trade secrets. However, even if laws and regulations are not violated, this can be a major problem if stakeholders such as residents are not receptive to smart-city services. While digital technology is an important enabling technology for smart cities, it should be recognized that the risk of data leakage is not zero, especially when dealing with personal information and trade secrets. It is important to explain the risks of data collection and use to data providers, and to fully explain the balance of risks and benefits to stakeholders to gain their consent for data use. In this chapter, the basic concept of data governance, following the approach of our Smart-City Data Governance Guidelines, will be explained.