The development of product-service systems (PSSs) has become one of the most prominent ways in which to promote a circular and resource-efficient economy. These systems shift the focus from selling products as commodities to offering solutions that fulfil customers’ needs and provide added value. PSSs have gained attention due to their potential to foster sustainability, particularly in the context of the circular economy and resource efficiency. This review article analyzes the literature on PSSs for the period of 2016–2022, aiming to explore the links between PSSs, sustainability, circular economy, and resource efficiency. Close to 160 relevant articles were identified and examined. The overall findings reinforce contributions from previous studies, which denote a tendency towards sector-specific studies, barriers, and stimuli to implementation and adoption, and PSS design methodologies in specific industries and sectors. The overall results show a steady growth of PSS literature, as well as consistency in its definition, despite variations according to the perspective from which the topic is analyzed. This study focuses on eight main trends in PSS research, along with eight challenges that arise in its design, implementation, and adoption, identifying avenues for future research.