Abstract We developed a deliverability model to predict the performance of multilateral wells. We first constructed a horizontal lateral model, which couples a reservoir inflow model with a wellbore flow model to calculate the production rate from each lateral. Pressure drop along the lateral was considered in the model. Then we implemented the lateral model into a well system with more than one lateral commingled to a main wellbore. The production from each lateral, the overall production rate, and the pressure in the well system are predicted by the multilateral deliverability model. For reservoir inflow, we have developed a new model using an imaging well method to calculate a single-phase inflow performance relationship (IPR) for a segmented horizontal lateral. The results from the new model are compared with existing analytical models. For flow in the laterals, we adopted single phase and two phase wellbore flow models. The single-phase lateral flow model incorporates frictional and accelerational pressure drop, and also the pressure drop caused by inflow turbulence. The two-phase lateral flow model uses the Beggs-Brill correlation or Ouyang’s homogeneous model which accounts for the effects of wall inflow, acceleration and flow patterns.The pressure drop in the tubing from the upper most lateral to the surface was calculated using a two-phase flow correlation. We present example calculations for a well with three laterals draining separate reservoirs. The examples illustrate the effect of interference between laterals on lateral and overall well performance.