The increasing global energy demand and environmental concerns around fossil fuels have been propelling research on biodiesel. Despite the benefits of biodiesel to the environment, its properties as a fuel are still not ideal. Babassu oil produces good quality biodiesel, but there are problems associated with its use as a fuel, mainly due to its susceptibility to oxidation. One way of improving the oxidative stability of biodiesels is by adding substances capable of hindering the oxidation process, the antioxidants. Most antioxidants used for biodiesel are synthetic antioxidants opposing the premise of using biodiesel, which is to be a better environmentally friendly alternative. Therefore, in this study three natural antioxidants were tested in the babassu biodiesel, for which an experimental design 23 was used. The viscosity, specific mass and oxidative stability of the samples were evaluated, and to determine the best conditions for the use of antioxidants, a statistical analysis was performed applying a variance analysis and the response surface methodology. It was verified that there was an improvement in the oxidative stability of babassu biodiesel for all the natural compounds tested with an improvement ranging from 52 to 92%. (c) 2020 Elsevier Ltd. All rights reserved.