A method for performing antenna tuning control of a wireless transceiver device in a wireless communications system and associated apparatus are provided. The method may include: during a tuning stage among multiple stages, utilizing a communications control circuit within the wireless transceiver device to obtain predetermined characterization data of at least one impedance-related tuning component regarding antenna tuning of at least one antenna from a storage device within the wireless transceiver device, where the at least one impedance-related tuning component includes at least one aperture tuner (APT); during the tuning stage, utilizing the communications control circuit to measure voltage standing wave ratio(s) (VSWR(s)) of any antenna among the at least one antenna; and during the tuning stage, utilizing the communications control circuit to determine at least one setting of the at least one impedance-related tuning component according to the predetermined characterization data and the measured VSWR(s), for antenna performance optimization.