One embodiment of the present invention relates to a method for receiving a sidelink synchronization signal (SLSS) by a terminal in a wireless communication system, comprising the steps of: receiving a physical sidelink broadcast channel (PSBCH); determining which of global navigation satellite systems (GNSS) or an eNB is to be a synchronization source according to priority information included in the PSBCH; and receiving an SLSS associated with the determined synchronization source, wherein the terminal determines that the priority information is valid only when a public land mobile network (PLMN) associated with the priority information matches a PLMN to which the terminal belongs.