In order to investigate the influence of the maximum aggregate size on the shear behavior of beams without shear reinforcement, 16 reinforced concrete beams subjected to concentrated loading were tested. The main parameters are the maximum aggregate size and span-to-depth ratio. Based on the test results, the failure mode, the ultimate shear capacity, the load-middle deflection curves and the relative displacement between crack lips were analyzed. Combined with a comparison of the test data and those published in the literature, the tested shear capacity was compared with the predicted value of GB 50010-2010, ACI 318-08, EC 2-02 and CSA 23.3-04. It can be concluded that the aggregate interlock is the main mechanism of shear transfer in beams without shear reinforcement, and that shear design methods should be established on the basis of accounting the critical influence of aggregate interlock on the beam-shear behavior of reinforced concrete members.