There is provided an opto-electric hybrid board with slight or no warpage. An opto-electric hybrid board according to the present disclosure includes an electric circuit board and an optical waveguide formed in a stacked manner on one surface of the electric circuit board. The optical waveguide includes an under cladding layer, cores for an optical path formed on a front surface of the under cladding layer, and over cladding layer formed on the front surface of the under cladding layer so as to cover the cores. A groove for prevention of warpage which has a bottom positioned below a top surface of the cores is formed at least in a front surface portion of the over cladding layer.