The unified Model of Electronic Government Adoption (UMEGA) was developed to bring novel insight into the context of citizen adoption of e-government services. As UMEGA is a recently evolved model, it demonstrates unequivocally the necessity for evaluating this model tailored to adopting e-government from the citizens’ perspective. The current study aims to perform a systematic literature review on the empirical validation of the UMEGA accomplished in several countries since its inception in 2017 by following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PRISMA is performed to synthesize the findings and analyze the performance of the constructs of the UMEGA. The systematic literature review encompassed the general characteristics, overall descriptive statistics, and synthesis of the constructs, analytical tools, and findings of the selected empirical articles. In the present study, the meta-analysis offered a strong confidence and prediction interval and significant combined effect size, suggesting that the constructs of the UMEGA, namely, performance expectancy, social influence, perceived risk, and facilitating conditions, significantly influenced attitude and behavioral intention to use e-government services. The association between attitude and behavioral intention is also found to be significant. The heterogeneity of the true effect of behavioral intention among empirical studies was partially explained by subgrouping in terms of sampling techniques, and E-government Development Index (EGDI) moderated the association between attitude and behavioral intention. The current study’s findings can serve as a solid foundation for knowledge expansion, easing the way for theoretical development and helping the government understand what aspects need to be considered while establishing initiatives to enhance the utilization of e-government services.

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