A method and an apparatus for transmitting a frame in a wireless LAN are disclosed. The method for transmitting a frame in a wireless LAN comprises: by an STA, receiving an uplink transmission instruction frame from an AP; and by the STA, transmitting, to the AP, a first uplink frame as a response to the uplink transmission instruction frame, wherein the uplink transmission instruction frame instructs transmission of the first uplink frame and a second uplink frame on overlapping time resources, the first uplink frame is transmitted at a transmission timing determined on the basis of UIFS, and the UIFS may be a fixed value.