The present study is devoted to the investigation of N2O formation characteristics in dielectric barrier discharge (DBD) reactor for environmental application. The effect of operating parameters, such as specific energy density (SED), O-2, concentration, NO initial concentration, and residence time on N2O concentration was investigated in dry O-2/N-2 mixtures. N2O formation from bulk gas (O-2 and NO is inevitable in DBD chemical process and was observed in all DBD reactors. N2O concentration shows an exponential increase or decrease with the variation in operating parameter. The experimental results show that N2O concentration first increases and then reaches saturation with the increase in SED and O-2 concentration, respectively. N2O concentration shows a monotonic increase with increasing residence time. N2O concentration decreases with NO concentration increasing from 50 ppm to 600 ppm. The N2O formation is enhanced with gamma-Al2O3 pellets packing into the DBD reactor compared with that of DBD reactor alone.