This application provides an antenna system and a wireless device, and pertains to the field of communications technologies. In this application, a decoupling resonator is connected to a first antenna, and a resonance frequency of the decoupling resonator is within an operating frequency band of a second antenna, so that the decoupling resonator can resonate within the operating frequency band of the second antenna. The decoupling resonator reduces coupling between the first antenna and the second antenna, and isolation between the first antenna and the second antenna is improved.