This study compared the water requirements, evapotranspiration (ETc), crop coefficient (Kc) and water use efficiency (WUE) of Elaeis guineensis Jacq. and the interspecific hybrid OxG during the nursery stage under varying irrigation levels. Using a randomised block design, four irrigation treatments were applied [0.3, 0.6, 0.9 and 1.2 times evaporation (EV)]. Results showed that the OxG hybrid outperformed E. guineensis in terms of vegetative growth, biomass production and WUE, especially under the 0.9 and 1.2 EV treatments. ETc values for the OxG hybrid ranged from 4.7-6.1 mm day⁻¹, while E. guineensis showed values from 5.2-6.6 mm day⁻¹. The Kc values ranged from 0.30-1.47 for E. guineensis Jacq. and from 0.90-1.39 for the interspecific hybrid OxG. Additionally, the OxG hybrid exhibited 44% higher WUE (0.26 g mm⁻¹) compared to E. guineensis (0.18 g mm⁻¹), demonstrating its greater efficiency in water use. The novelty of this study lies in the detailed comparison of the two cultivars’ water use characteristics, providing insights into more water-efficient cultivars and supporting the development of precise irrigation strategies. These findings contribute to a more sustainable oil palm cultivation by optimising irrigation management and conserving water resources, particularly in regions facing water scarcity.