The requirement for minimum shear reinforcement in reinforced concrete beams is evaluated based on the treatment of interface shear transfer across a crack. A key parameter for this derivation is the required magnitude of contact normal stress on such interfaces, which controls the frictional shear resistance. Recent experimental data were employed to define the required value of the normal contact stress, and its incorporation into the proposed approach resulted in a modified definition for shear reinforcement. This approach enabled the derivation of two useful tools for the design of interface shear resistance and minimum shear reinforcement in reinforced concrete beams.