A method and apparatus for data transmission considering feedback and sidelink resource allocation in a wireless communication system is provided. A wireless device enables a hybrid automatic repeat request (HARQ) feedback for a logical channel, selects to create a sidelink grant corresponding to transmissions of a single media access control (MAC) protocol data unit (PDU) or multiple MAC PDUs, and performs transmission resource reselection check. When there is no sidelink grant for which the HARQ feedback is enabled on a carrier, the wireless device triggers TX resource selection on the carrier.