The effect of an electrostatic crystal-field (CF) model on energy levels and oscillator strengths for Nd3+:YAG (where YAG denotes yttrium aluminum garnet) has been studied. Three parameters for the correction of the Slater integrals F2, F4, and F6 and one parameter to correct the spin-orbit constant for the effects of the linear configuration interaction have been introduced. The complete 364×364 energy matrix has been diagonalized directly. The various polarizabilities and shielding parameters used have been calculated by ab initio methods. All Stark levels within the Nd3+(4f3) configuration are presented. The calculated Stark splittings agree well with experiment. The electrostatic CF model used is therefore believed to be satisfactory. The eigenvectors of the complete energy matrix have been used to calculate oscillator strengths, which agree well with experiment. A refined Judd-Ofelt theory has been used. The Judd-Ofelt intensity parameters Ωλ are presented and found to be in excellent agreement with experiment. The temperature dependence of the spectrum is studied using a molecular-dynamics approach.