It has often been argued that people can attribute mental states to robots without making any ontological commitments to the reality of those states. But what does it mean to 'attribute' a mental state to a robot, and what is an 'ontological commitment'? It will be argued that, on a plausible interpretation of these two notions, it is not clear how mental state attribution can occur without any ontological commitment. Taking inspiration from the philosophical debate on scientific realism, a provisional taxonomy of folk-ontological stances towards robots will also be identified, corresponding to different ways of understanding robotic minds. They include realism, non-realism, eliminativism, reductionism, fictionalism and agnosticism. Instrumentalism will also be discussed and presented as a folk-epistemological stance. In the last part of the article it will be argued that people's folk-ontological stances towards robots and humans can influence their perception of the human-likeness of robots. The analysis carried out here can be seen as encouraging a 'folk-ontological turn' in human-robot interaction research, aimed at explicitly determining what beliefs people have about the reality of robot minds.