With numerous ecosystem services of urban green spaces (UGS), contributing to sustainability and a better quality of life, UGS provision is perceived as a pivotal role in urban planning. However, concern arises as to what extent local governments have effectively provided good quality and adequate quantity of UGS for the public? Provisioning those UGS aspects has been given a low priority due to insufficient resources and the limited budget allocated by local governments. As such, maintenance and management effectiveness of UGS is detrimentally affected, resulting in disused, overused spaces and thus hot spots for crimes. Therefore, public monetary contribution via taxation is suggested as an alternative to ensuring the continuity and sustainability of UGS services. This review paper is vital to identify and showcase specific factors and mediators, influencing the willingness to pay (WTP) of residents/users for UGS services. Methodologically, after conducting Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for the purpose of article screening and selection based on the two primary databases (Google Scholar and Elsevier), this paper reviewed 18 journal articles, from the year 2013 to 2020. Along with the indirect sub-factors, namely environmental behaviour/attitude and socioeconomic profiles of users, there are three main spatial and non-spatial variables (factors) identified: (i) accessibility/proximity to the nearest UGS; (ii) quantity/adequacy of UGS; and (iii) quality of UGS within a township area, influencing satisfaction and enjoyment as well as reasons and frequency of park visiting of users (mediators), which consequently affect their WTP for UGS.