Diverse human activities are carried out in real estate, suggesting its significant contribution to global warming. This study examines how cognizant managers of real estate are about the potential benefits of vertical greening systems (VGSs). The research questionnaire was administered to real estate managers. The real estate managers were those under the employment of registered estate surveying and valuation firms in Lagos. They were sampled using the simple random method, with one real estate manager selected per firm. Of the total of 282 real estate managers, only 127 responded to the questionnaire, and 121 (representing 42.9%) were found to be of use in the data analysis. With the aid of the Statistical Package for the Social Sciences (SPSS v.20). The analysis of the data collected was done using the fuzzy synthetic evaluation method. The study found a generally low level of cognizance among the real estate managers (overall cognizance index = 2.60). However, based on the categories of the different benefits of VGSs, the results showed that the real estate managers' cognizance of the environmental benefits of VGSs is more than that of its social and economic benefits. Real estate managers not being fully cognizant of the potential benefits of VGSs would prevent them from giving an appropriate recommendation to the government on the need to form a policy that would mandate the installation of vegetation on buildings. We conclude that the cognizance of the real estate managers would assist the government in the formulation of policies to foster the achievement of sustainable development goals.