Integrating urban green infrastructure (UGI) into cities is receiving increasing attention owing to its potential to provide various urban ecosystem services (UES). This review assesses the multifaceted services of UGI as benefits and co-benefits. By combining systematic and narrative review processes, we aim to synthesise existing knowledge along six current themes and identify research gaps. A total of 690 peer-reviewed articles published during 2000–2020 from Web of Science were selected, followed by bibliometric and full-text analysis. Based on the frequency of appearance in the network visualisation of keywords, six themes of current trends were identified, namely: (1) benefits of UGI as UES; (2) mitigating climate and urban climate impacts by UGI; (3) UGI contribution to sustainable development goals; (4) reconceptualising greenspaces as ‘safe havens’; (5) public acknowledgement and supportive governance for UGI; and (6) rethinking the operationalisability of UGI. The first two themes represent existing focus on categories of ecosystem services, the next two encompass broader emerging co-benefits and the last two focus on how to operationalise UGI and support widespread adoption and implementation. Within Theme 2, the most frequently discussed service with the largest number of research, we conducted a detailed analysis of the methods and content focus in the existing literature. Through a narrative review, we identified 15 research gaps throughout these 6 themes. This review provides a comprehensive overview for urban researchers and practitioners to inform the integration of urban green infrastructure into urban planning and management.