Middle-income countries (MICs)—thelargest group of World Bank Group clients—are criticaldrivers of the world economy, but they remain vulnerable toglobal shocks. Addressing the development challenges facingMICs can generate positive externalities and transferableknowledge to lower income countries. According to the 2017World Bank Group document, “Forward Look: A Vision for theWorld Bank Group in 2030—Progress and Challenges,” to meetits twin goals of eradicating extreme poverty and ensuringshared prosperity in a sustainable manner, the World BankGroup must sustain and evolve its engagement with MICs. Thissynthesis review focuses on the World Bank Group’sengagement with upper-middle-income countries (UMICs) andconcludes that the Bank Group’s support to them remainshighly relevant from two perspectives: helping thesecountries address their specific developmental challenges,and potentially having a valuable demonstration effect forother lower-income groups of World Bank Group clients. Themore successful programs the World Bank Group supported weregenerally long duration and went well beyond the scope of asingle investment loan or development policy loan. The WorldBank Group’s willingness to sustain its engagement and buildclose relationships at the technical level contributed tosuccessful outcomes. Despite this high relevance, importantchallenges remain in fully addressing some of the structuralissues that underlie UMIC’s vulnerability to various shocksand in making progress that is more significant andsustained in several important development areas. Thegeneral perception is that World Bank Group financing isdiminishing in UMICs, but the World Bank continues itsimportant dialogue and engagement with UMICs despite thisperception, covering a wide range of issues from fosteringcountercyclical policies, to building resilience, tofinancing large infrastructure projects, to catalyzingprivate sector participation. IEG evaluations consistentlyemphasized the high relevance of the World Bank’s analyticwork in supporting reforms in UMICs and the high value thatcountry stakeholders in UMICs assigned to its analyticalwork and technical assistance. Going forward, there is scopefor further work on analyzing World Bank Group performanceacross various groups and subgroups of clients, includingwithin narrower technical areas.