This work reports the use of Moringa oleifera oil and leaves as potential sources for the production of biodiesel and antioxidant additives for biodiesels, respectively. The M. oleifera methyl ester was prepared by a two-step reaction and exhibited physical–chemical properties that met the minimum or maximum limits of the EN 14214, emphasizing the high induction period (IP) of 19.3 h. Ethanolic extracts of M. oleifera leaves were evaluated as additives to increase the IP value of biodiesels. The results indicate that the 98% (v/v) ethanolic extract increased IP values of soybean biodiesel from 3.8 to 10.3 h using the 100 μg g⁻¹ of extract, showing better performance than the synthetic antioxidant tert-butyl-hydroquinone. The extract also provided similar efficiency to methyl esters produced from sunflower, colza, corn and residual cooking oils. These results evidence the promising use of M. oleifera not only for biodiesel production but also as a source of antioxidant additives for biodiesels with low oxidation stability.