Cross sections were measured for the 75As(n,p)75Ge, 75As(n, α)72Ga, 75As(n,2n)74As, 74,76,78Se(n,p)74,76,78As, 78,80Se(n,α)75,77Ge, 72,73,74Ge(n,p)72,73,74Ga, and 70,76Ge(n,2n)69,75Ge reactions over the 6.3- to 14.7-MeV neutron energy range. Samples of As2O3, selenium, and germanium or GeO2 of natural isotopic abundance were used. The neutrons were produced via the D(d,n)3He reaction using a deuterium gas target at a variable energy cyclotron (En = 6.3 to 11.9 MeV) and via the T(d,n)4He reaction using a solid titanium-tritium target at a neutron generator (En = 14.7 MeV). The activation technique was used in combination with high-resolution gamma-ray spectroscopy. The experimental excitation functions are well reproduced by the nuclear model calculations, based on statistical multistep reaction theory.