Study region: The Loess Plateau (LP), China Study focus: Ecological restoration on the LP has substantially enhanced ecosystem services (ESs), but at the cost of significant water resource depletion, highlighting the urgent need to improve water use efficiency. Based on the concept of ecosystem water use efficiency, we proposed a new indicator-Ecosystem Services Water Use Efficiency (ES_WUE), defined as the ratio of ESs to actual evapotranspiration. We assessed three key ESs-water erosion prevention, wind erosion prevention, and carbon sequestration-across the LP from 2000 to 2020, and quantified corresponding ES_WUE. Subsequently, we examined their spatiotemporal patterns, and explored key influencing factors using multiple statistical models. New hydrological insights for the region: The ES_WUE extends traditional water use efficiency by integrating multiple ESs, enabling a holistic evaluation that supports sustainable and balanced ecological restoration planning. Results showed that vegetation coverage precipitation, aridity index, slope, and elevation were the primary factor influencing spatial variations in ES_WUE. Temporal changes in aridity index, potential evapotranspiration, and vegetation coverage were the main drivers of ES_WUE dynamics. Grassland expansion was found to positively contribute to the three ES_WUE. Moreover, ESs had a stronger influence than actual evapotranspiration on spatiotemporal variations in ES_WUE. This study offers a novel perspective for ecological restoration in water-limited regions, emphasizing reducing water consumption for enhancing ESs by focusing on ES_WUE.