In the reported work the influence of the fluidized-bed hydrodynamics on selectivity and yield to a desired product was investigated for competitive reactions with different reaction orders. The analysis was performed by means of reaction engineering simulations. For the parallel reactions exhibiting lower reaction order with respect to the reactant(s) for the selective step than for the non-selective ones higher selectivity can be achieved in a fluidized-bed reactor than in a fixed-bed one. The high selectivity in a fluidized-bed reactor is due to the low concentrations of reactants in the emulsion phase where the catalytic reactions take place. This low concentrations, in turn, are due to the mass transport limitation between bubbles and the emulsion phase as well as backmixing of gas in the emulsion phase.