An apparatus and method for handling in-device co-existence of NR V2X and LTE V2X sidelinks are disclosed. The apparatus includes a transceiver that is scheduled to transmit and/or receive a first data transmission over a first radio access technology (RAT) and a second data transmission over a second RAT; and a processor that detects collision between the first data transmission and the second data transmission; wherein, upon detection of collision, the processor further controls the transceiver to selectively drop one of the data transmissions based on a set of selection criteria, the set of selection criteria including: priorities of the first RAT and the second RAT, and an attribute of the second data transmission indicative of whether it is an initial transmission or a retransmission.