A method and apparatus for Sidelink (SL) Discontinuous Reception (DRX) operation based on resource allocation is provided. A first wireless device, e.g., receiving user equipment (RX UE), monitors first Physical Sidelink Control Channel (PSCCH) transmissions from a second wireless device, e.g., transmitting UE (TX UE), in a Sidelink (SL) active time for SL Discontinuous Reception (DRX). The first wireless device receives, from the second wireless device, an indication to reselection of sidelink resources, and adjusts the SL active time based on the indication. The first wireless device monitors second PSCCH transmissions from the second wireless device in the adjusted SL active time.