Disclosed is inexpensive optical waveguide for an optical connector which is accurately positioned across the width of cores when inserted in and fixed in an optical waveguide fixing through hole of a ferrule to provide low optical coupling loss when connected, an optical connector using the same, and a method of manufacturing the same. An optical waveguide for an optical connector includes cores, an under cladding layer, and an over cladding layer. The strip-shaped optical waveguide has a longitudinal end portion configured to be fixed in a predetermined through hole provided in a ferrule of an optical connector. The cores are formed on the under cladding layer by a photolithographic method. The over cladding layer is formed with respect to the positions of the cores or positioning alignment marks by a photolithographic method. The over cladding layer covers the cores, and the under cladding layer including crosswise end surfaces thereof.