Until now, only a limited amount of research has been carried out on addressing attitudes towards sport horse welfare (AHW). In order to contribute to filling this gap, the goals of this study were two-fold: the investigation of the influence of different demographic factors and factors related to equestrianism on the AHW and the demonstration of the applicability of Partial Least Squares Equation Modelling (PLS) in this field of research. An online survey was conducted among 2,947 equestrians. A research model was established based on eleven factors, which were investigated for their potential influence on the AHW and their relationships to each other. This model was analysed by means of PLS which, to the best of our knowledge, has not been used before to investigate human attitudes towards horses (Equus caballus). The results show that the factors with the highest impacts on the AHW were the affection for animals, the attitude towards classically organised equestrianism and the utility orientation. Gender, income, agricultural background, tradition, brand orientation and the importance of breed and pedigree were also found to exert a significant influence on the AHW. In contrast, age and involvement in horse-riding as a hobby were found to have no effect on the AHW. Furthermore, several significant relationships could be identified among the different factors. In conclusion, the present study provides an insight into the factors influencing the complex AHW and demonstrates the applicability of the PLS for research in this field.