The flow ability of granular materials is affected by many factors including size and shape of the grain kernels and dockage and their moisture contents. All these factors influence the internal friction among grain kernels during grain loading and unloading. Therefore, understanding the internal friction among grain kernels is critical for designing grain handling equipment and storage facilities. To evaluate the effects of the internal friction of wheat kernels at different moisture contents, direct shear test at the normal pressures of 0 and 250 kPa was conducted on clean wheat samples. The cohesion and internal friction angles were determined by using the shear test data. A model was developed to predict the cohesion and internal friction angles of the wheat bulk in flat bottom cylindrical silos based on Janssen's theory. Wheat with a moisture content of 7.5% has higher cohesiveness and a lower friction coefficient as compared to the samples with a moisture content of 10%. More data on different wheat moisture contents will be collected and presented.