Conventional study and practice of data governance, which is a set of processes of governing any data pertain to information systems, have been made around master data management and data quality management of structured data. The dawn of the big data era, which occurred around the year of 2011, has drawn enterprises' attention to ways to process, utilize and extract value out of the vast quantity of data brought about by system logs, sensors, SNSs and so on. Academic research aiming towards expansion of a data governance framework to cope with the era of big data is still few, albeit its significance in the industry. This article overviews existing research work of data governance and discusses future directions of data governance research.