An operation method of a first terminal in a communication system is provided. The method includes configuring sidelink (SL) bandwidth parts (BWPs) used for groupcast sidelink communication and transmitting a configuration information message including configuration information of the SL BWPs to participating terminals participating in the groupcast sidelink communication. The groupcast sidelink communication is performed with the participating terminals using one or more SL BWPs among the SL BWPs. In response to determining that reconfiguration of the SL BWPs is necessary, the SL BWPs are reconfigured and a reconfiguration information message including reconfiguration information of the SL BWPs is transmitted to the participating terminals.