Different forms of direct paternal investment have been described in mammals. One such species where paternal care was noticed, but remains poorly understood, is the horse (Equus caballus), where the male keeps a long-term relationship with several females and offspring. Therefore, the aim of this study was to analyse the interactions between the harem stallion and his foals. Two herds of Exmoor ponies living under semi-feral conditions in two separate reserves within Czech Republic were studied, each during one of the two consecutive breeding seasons (in 2016 and 2017). Both herds consisted of a stallion, 14 mares and their offspring (12 and 10 foals). The behaviour of all group members was recorded focusing on the stallion-foal interactions. The results show that the stallion receives more friendly interactions, snapping and playful behaviour from foals compared with adult mares. Furthermore, the stallion is more tolerant than mares, and actively plays with his offspring. There is no statistical difference in the sex of the foals in the stallion-foal interactions; however, male foals are more active than female foals in interacting with their father. The probability of a certain behaviour occurring between adult and foals changed over time. The stallion's presence might, therefore, be crucial for the physical and psychological development of the foals, especially the colts. These results may bring new insight into the common management of domestic horses, where stallions are usually kept separately and are not allowed to form natural groups.