A method and apparatus for discontinuous reception (DRX) of downlink signal for sidelink transmission is provided. A wireless device operating in a wireless communication system monitors a physical downlink control channel (PDCCH) carrying a sidelink grant during an active time including a time interval for which a scheduling request (SR) is transmitted on a physical uplink control channel (PUCCH) and is pending, based on the SR being triggered for a sidelink buffer status report (SL BSR) and/or a sidelink channel state information (SL CSI) reporting.