Maintaining game animals under intensified captive conditions for production or ecotourism purposes has increased over recent years. This is especially true for the common eland, which was identified as an ideal species for captive production conditions due to its temperament and adaptability. However, little has been done to understand their social behaviour under captive conditions, especially when implementing management tools such as immunocastration, which is often used in wildlife in zoological gardens for contraception and may also aid in easing the management of eland males within mixed-sex herds in captivity, but which could potentially have adverse effects on the hierarchical rank of the immunocastrated animal, and thus welfare from a social perspective. Therefore, this study monitored the behaviour and hierarchical structure of captive common eland and the effects of immunocastrating male eland on their social rank, aggressive vs affiliative behaviours, and activity budget. Thirty common eland were divided into two groups consisting of sub-adults (n =15; ≈2 years old) and juveniles (n =15; ≈6 months old). Each group consisted of five intact males, five immunocastrated males, and five females. Vaccinations (Improvac®, 2 mL per dose) were administered to the males assigned to the immunocastration treatment during week 3 and again in week 7 of the study. Behavioural observations were conducted every two weeks from week 1 of the study, for five months, using all occurrence sampling for dyadic social interactions and scan sampling for activity budget behaviours. The hierarchical structure of the two groups was examined, and the rates and proportion of dominant, aggressive and affiliative interactions were established using DomiCalc. The pre-vaccination period and the control animals (not vaccinated) were used as categories of reference. Overall, immunocastration reduced aggressive behaviour in juveniles, with no effect on activity and other agonistic behaviours. However, juveniles and subadults decreased their feeding behaviour post-vaccination and were more active socially. Immunocastration can potentially be used for controlling agonistic behaviour in farmed common eland.