An EAM interatomic potential for the ordered AlMo3 intermetallic is developed and applied to the study of point defects in the AlMo3. The equilibrium concentrations of vacancies and antisites are calculated using statistical thermodynamics. Results show that antisites are the most abundant type of defect in a range of temperatures and compositions close to stoichiometry. Finally, the diffusion by vacancy mechanism in the same structure is studied through the kinetic Monte Carlo technique. Possible atomic mechanisms of diffusion are suggested and analyzed in some detail.