Three existing strength criteria for composite materials have been ex tended to account for the statistical behavior of ultimate strength of glass- epoxy composites. The basic distribution functions for the longitudinal, the transverse and the in-plane shear strengths were obtained by fitting the experimental data into a two-parameter Weibull distribution. These three functions were then used to predict the strength distribution of the com posite under off-axis loads. Theoretical and experimental results were com pared and discussed.