This study introduces a water-driven crop model aiming to quantitatively link olive yield to climate and soil moisture dynamics using an ecohydrological approach. A mathematical model describing soil moisture, evapotranspiration and assimilation dynamics of olive orchards is developed here. The model is able to explicitly reproduce two different hydroclimatic phases in Mediterranean areas: the well-watered conditions in which evapotranspiration and assimilation assume their maximum values and the real conditions where the limitations induced by soil moisture availability are taken into account. Annual olive yield is obtained by integrating the carbon assimilation during the growing season, including the effects of vegetation water stress on biomass allocation. This numerical model has been tested on an olive orchard located in Sicily (Italy) obtaining a satisfactory reproduction of historical olive yield data. This model is useful for simulating the influence of soil moisture dynamic on biomass growth, fruit productivity, also in a context of climatic change. Copyright © 2011 John Wiley & Sons, Ltd.