A running board support assembly (200) for fastening a running board step (104) to a vehicle includes a support bracket (204) for engagement with the running board step, and a mounting bracket (202) for coupling the support bracket (204) to the vehicle. The mounting bracket (202) includes a hooking end (212) and a pin (214). The support bracket (204) includes a hook (226) for engagement with the hooking end (212), and an aperture (218) for engagement with the pin (214). When assembled, the hook (226) and the aperture (218) cooperate to tension the mounting bracket (202) and thereby secure the support bracket (204) to the mounting bracket (202).