Abstract This research has as its objective the discovery of the critical factors that enable citizens to adopt e-Government (e-Gov) at different stages of service maturity. To accomplish the objective, this research has explained the related concepts and theories and developed a research framework grounded on a strong theoretical and literature review background. The empirical study was conducted in Canada, which is a leader in providing mature e-Gov services. From our results, we have observed two ontological differences from the present literature in the adoption behavior of e-Gov where organizational and financial perspectives have distinct implications over parsimonious technology adoption behavior. First, technology adoption model (TAM), diffusion of innovation theory (DOI), and theory of planned behavior (TPB) cannot capture and specify the complete essence of e-Gov adoption behavior of citizens. Second, e-Gov adoption behavior also differs based on service maturity levels, i.e., when functional characteristics of organizational, technological, economical, and social perspectives of e-Gov differ. Our findings indicate the critical factors that enable citizens to adopt e-Gov at different stages of service maturity. Public administrators and policy-makers have potential implications from the findings of the adoption behavior of e-Gov at different maturity levels.