Current frameworks on running-related injury (RRI) aetiology emphasise the relation between exposure to training load, internal tissue loads, and tissue capacity; with tissue load exceeding its capacity being the key biological mechanism in the development of RRI. Despite this, runners and clinicians commonly attribute improper prescription of running shoes as a primary causative factor for RRI. A likely contributor to this belief may be the marketing produced by the footwear industry, which often is not supported by scientific evidence. The purpose of this study was to examine the beliefs of running shoe salespersons and physiotherapy students regarding the influence of running shoes and foot pronation on RRI. A questionnaire was distributed to 275 physiotherapy students at three different Swedish universities and to 219 running shoe salespersons of 35 different running shoe stores. A total of 270 students and 89 salespersons responded to the questionnaire. Salespersons rated their knowledge of running shoes (r = −0.56), foot pronation (r = −0.55) and RRI (r = −0.34) higher than students did (p <.001). A minority of students (32.4%) and salespersons (14.1%) reported training errors to be the main contributing cause of RRI. A majority of salespersons (52.5%), but not students (15.3%), reported more expensive shoes to be better at preventing RRI than cheaper shoes. Most salespersons (51.9%), but not students (39.0%), would recommend uninjured runners to change their current running shoe type despite runners being satisfied with their current shoes. Despite salespersons being more confident in their knowledge of running shoes and foot pronation with relation to RRI development than students, both populations hold beliefs that do not align well with current frameworks on RRI aetiology.