A method, performed by a network node, is disclosed, for configuring resources to be used for Wake-Up Signal, WUS, transmission to a plurality of wireless device groups in the communications network. The method comprises obtaining a number of wireless device groups supported by the communications network. The method comprises allocating, based on the obtained number of wireless device groups supported by the communications network, one or more active resources, out of a set of available resources, for WUS for the number of wireless device groups. The method comprises determining, based on a set of resource configuration criteria, a WUS resource configuration defining a mapping of the wireless device groups to the determined one or more active resources. The method comprises providing, to the wireless device, a set of resource configuration parameters indicative of the determined WUS configuration.