Abstract: A nonlinear stochastic model has been formulated to simulate the stress-strain behavior of strandbased wood composites based on the constitutive properties of the wood strands. Prediction models of this type save time and money in the development of wood composites by computationally gauging the effects of varying raw material characteristics with limited fabrication and testing of the full-scale product. The proposed model uses a stochastic-based materially nonlinear finite-element code with extended capacity to perform Monte Carlo simulations to predict the stress-strain behavior of s and s angle-ply laminates in tension and compression. The nonlinear constitutive behavior of the wood strands is characterized within the framework of rateindependent theory of orthotropic plasticity, where the plastic flow rule is in accordance with the Tsai-Wu criterion. Shear strength and stiffness of the strands, as well as the interaction parameter of the Tsai-Wu criterion have been estimated through a minimization technique developed in the present study. The model’s accuracy was validated through comparisons of the numerical simulation results and experimental data. Excellent agreement was found.