The destruction of nitrous oxide in oxygen using plasma and post-plasma catalytic treatments was investigated experimentally in atmospheric-pressure dielectric barrier (DBD) and gliding arc (GAD) discharges. In the DBD, 7% of the N2O is destroyed with 70% selectivity to NOx whereas the GAD gives rise to greater conversion (23%) with lower NOx selectivity (30%). A gas-phase plasma kinetic model was developed and used to analyse the chemical reaction pathways involved in the plasma environment: in the room temperature DBD, the primary destruction process is reaction with O(D-1), with the branching ratio to form 2NO versus N-2+O-2 determining the product selectivity. On the other hand, in the hot GAD environment (900K), the reaction of ground-state O with N2O to form N-2+O-2 becomes more important. The use of a catalytic bed after the DBD reactor resulted in significant enhancement of N2O conversion from 6.8 to 28.0%. A surface mechanism for the catalytic dissociation of N2O in the presence of O-3 is proposed, whereby N2O reacts with the adsorbed atomic oxygen, released from ozone dissociation, to form N-2 and NO in approximately equal proportions.