We report a single-valued potential energy surface for HO4((2)A) from the double many-body expansion method. All n-body (n = 2-4) energy terms are taken from published studies on the relevant fragments, with st five-body energy term of Gaussian form added to mimic the experimental activation energy for the OH(v = 0) + O-3 reaction. A detailed dynamics study of this reaction is also reported using classical trajectories. Good agreement with existing experimental data is obtained.