A system and process for producing xylene and other alkylated aromatics includes one or more fluidized bed reaction zones that provide contact between the reactants (i.e., an aromatic reactant and an alkylating reagent). Improved conversion and selectivity is realized when the alkylating reagent is stagewise injected into the fluidized bed at one or more locations downstream from the location of aromatic reactant introduction into the fluidized bed. Preferably, the alkylating reagent is introduced at a plurality of locations along the axial direction of the fluidized bed reaction zone, or at plural locations between a plurality of different fluidized bed reaction zones.