Effective monitoring programmes are critical to understand and mitigate declining wildlife populations. In South Africa, the majority of oribi antelope (Ourebia ourebi ourebi ) occur on private rangelands as broadly distributed and highly-fragmented populations. Thus, to effectively manage such a species, conservation organizations rely on citizen science-led conservation initiatives, whereby members of the public provide data on oribi population demographics and potential threats. Using these data, we estimated the total oribi population size and assessed the population trend of oribi in KwaZulu-Natal, South Africa, over a 14-year period (2001–2014). We found that the oribi population has declined by 30% over the 14 years. However, oribi population estimates were highly correlated with the number of returned survey forms. This relationship makes it difficult to accurately assess population trends and almost impossible to determine if any changes in conservation management have influenced oribi populations. Thus, issues associated with citizen science and data quality (i.e. participation levels), may limit the ability of the oribi census to accurately inform oribi conservation and management. We discuss the value and limitations of citizen science in oribi conservation with the ultimate goal of improving citizen-led oribi conservation.