In the present study, we assessed for the first time the changes in the antioxidant capacity, total phenolic content, and polyphenolic composition of interspecific hybrid palm oil extracted from Elaeis oleifera × Elaeis guineensis (O × G, Coari × La Mé cultivar) during the fruit ripening process 18, 20, 22, and 24 weeks after anthesis. A progressive decrease (p < 0.05) of phenolic content occurred during fruit development together with marked changes in polyphenol profiles. Significant negative correlations were established between antioxidant activity measured by TEAC (R = -0.954; p < 0.05) and ORAC (R = -0.745; p < 0.05) and the fruit ripening stage, while a positive correlation between total phenolic content was found using either the TEAC assay or the ORAC assay. The highest DPPH radical scavenging activity was also obtained with oils extracted at 18 WAA. These results highlight that O × G fruits of early ripeness represent a better source of phenolic compounds and may provide extracts with higher antioxidant activities when hybrid palm oil is aimed to be used as a functional ingredient for the development of food or food products with antioxidant properties.