Video games are a massively popular form of entertainment, socialising, cooperation, and competition. Games’ ubiquity fuels fears that they cause poor mental health, and major health bodies and national governments have made far-reaching policy decisions to address games’ potential risks, despite lacking adequate supporting data. The concern-evidence mismatch underscores that we know too little about games’ impacts on well-being. We addressed this disconnect by linking six weeks of 38,030 players’ objective game-behaviour data, provided by six global game publishers, with three waves of their self-reported well-being that we collected. We found little to no evidence for a causal connection between gameplay and well-being. However, results suggested that motivations play a role in players’ well- being. For good or ill, the average effects of time spent playing video games on players’ well-being are likely very small, and further industry data are required to determine potential risks and supportive factors to health.