A method and a device for performing communication in a wireless LAN system are disclosed. A method by which a first station (STA) performs communication in a wireless LAN system may comprise the steps of: receiving, from an access point (AP), first information related to a restricted target wake time (r-TWT); receiving, from the AP, second information related to the extension of the end time of a service period (SP) of the r-TWT; and transmitting, to the AP, third information indicating whether to maintain an awake state until the end time of the extended SP.