The present invention concerns an automatic time-setting system for a portable object having an horological function. The present invention also concerns a portable object having an horological function capable of being automatically set to the right time, such as an electronic timepiece. According to the present invention, the portable object (100) includes means (11) for receiving an acoustic time-setting signal (50) and means (12, 13) for deriving time-setting indications (ho, mo) from this acoustic time-setting signal (50) allowing said time indication of the portable object (100) to be corrected. According to the present invention, the portable object may advantageously be set to the right time via an acoustic time-setting signal (50) transmitted for example by the loud speaker of a personal computer, a television, a radio or a telephone receiver.