The techniques for characterization of the shear strength of friction materials were reviewed and a new double-lap-shear test method was developed. Various types of friction materials were tested for shear strength by this new technique. The effects of different material properties and processing factors such as resin type, resin content, resin cure rate, fiber geometry, fiber content, and test environment on the shear strength of the friction materials were also examined. Positive correlations between the shear strength and the mechanical life of wet friction materials were established. Accurate determination of shear strength in wet friction materials is vital in predicting the performance and durability of friction materials for friction plates, transmission bands, and torque converter lockup clutches.