In this study, neutron incident reaction cross sections for some target nuclei such as 24 Mg, 27 Al, 28 Si, 56 Fe, and 63 Cu used in neutron activation analysis have been investigated. The new calculations on the excitation functions of 24 Mg(n, p) 24 Na, 27 Al(n, p) 27 Mg, 27 Al(n, α) 24 Na, 28 Si(n, p) 28 Al, 56 Fe(n, p) 56 Mn, and 63 Cu(n, 2n) 62 Cu reactions have been carried out for incident neutron energies up to 20 MeV. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new geometry dependent hybrid model and the full exciton model. Equilibrium effects are calculated according to the Weisskopf–Ewing model. In the present work, reaction cross-sections have been calculated by using empirical formulas developed for energies of 14–15 MeV. The calculated results are discussed and compared with the experimental data taken from the EXFOR database.