Human-animal relationships are based on a succession of interactions (positive or negative). Recent studies showed that horse are able to generalise their relationship with a specific person to other humans. In riding schools, horses are likely to be in touch with a wide variety of people, including young children. The quality of the human-horse relationship therefore is of a large importance for animals’ and humans’ (riders and caretakers) welfare and security. In the present study we compared reactions of horses from different riding schools towards humans in a variety of human-related tests. Results show large differences in the reactions of horses towards humans according to the schools. These differences can be related to horses’ housing (box / paddock, single / group…) and working (riders’ postures, teachers’ attitudes and behaviour) conditions. The results are discussed in terms of management, welfare and their impact on the human-horse relationship.