The question of the psychological validity of the notion of image schema has come up ever since it was incorporated into linguistics in the 1980s. Concretely: Is there any evidence that image schemas are “real” in any psychological or neurological sense? This chapter deals with this question, turning first to an overview of relevant research on the learning of mathematics in childhood and in school settings, given that it seems to provide substantive support for the notion of image schemas. It then looks at the nature of diagrams in mathematics as external models of inner image-schematic thinking. These can be used, inferentially, as a means to delineate the likely features of image-schematic cognition. Finally, the work being carried out on image schemas within AI is discussed as further corroboration of the soundness of the notion. This chapter ends with an overall assessment of image schema theory and its relevance to the study of math cognition.