The present invention relates to a wireless communication system, and discloses a method and apparatus for transmitting/receiving a signal in a wireless communication system that supports multi-user MIMO transmission. According to one embodiment of the present invention, a method in which a mobile station receives a signal in a wireless communication system that supports multi-user MIMO transmission, comprises: a step of receiving information on the entirety of the transmission rank of the multi-user MIMO transmission; a step of receiving a reference signal and data for demodulation for the mobile station on the basis of the information on the entirety of the transmission rank; a step of acquiring channel information on the mobile station from the reference signal for demodulation; and a step of demodulating said data on the basis of the acquired channel information.