A predistortion system uses spectral regrowth filtering in a feedback path thereof to reduce out-of-band error. An illustrative embodiment of the system includes a predistortion circuit which generates a predistorted signal, one or more signal processing elements configured to process the predistorted signal, and a feedback processing circuit coupled between an output of the one or more signal processing elements and a control input of the predistortion circuit. Associated with the feedback processing circuit is at least one spectral regrowth filter. The spectral regrowth filter is configured to pass an out-of-band portion of a feedback signal while attenuating an in-band portion of the feedback signal, and operates in conjunction with the feedback processing circuit to control one or more characteristics of the predistortion circuit.