There are provided measures for enabling/realizing flexible and adaptive QoS monitoring for unicast/groupcast over sidelink communication, which may preferably be capable of enhancing support of unicast/groupcast services over sidelink communication. Such measures exemplarily comprise obtaining a request for QoS monitoring for unicast/groupcast over sidelink communication with a specified quality-of-service profile, which indicates at least one target QoS metric to be monitored, determining a QoS monitoring procedure, wherein a scheme for enforcing QoS monitoring over sidelink communication in collaboration with at least one unicast/groupcast receiving-side device is decided, and performing the QoS monitoring procedure, wherein QoS monitoring messages are exchanged with the at least one unicast/groupcast receiving-side device over the sidelink communication with the specified QoS profile in accordance with the decided scheme and the at least one target quality-of-service metric is derived based thereon.