Openness in education is an evolving concept which is shaped by the changing needs of societies, cultures, geographies, and economies, thus, it does not have a precise definition. By focusing on four sets of generic keywords -- open education, open learning, open educational resources (OERs), and open educational practices (OEPs) -- this paper examines research in openness in education through a systematic review of peer reviewed literature. In doing so, the researchers sought to draw attention to existing trends and patterns and possible future trajectories of openness in education. Content analysis, social network analysis, and text-mining are the methods used for data collection and analysis. Findings show that there has been growing interest on openness in education, particularly on OERs, across different fields. Findings also point to OEPs as an emerging area of study, which offers a fertile ground for future research. However, on closer inspection, a divide can be observed between the global north and global south in terms of research output.