There are several studies that assess the influence of factors on citizens' intention to adopt e-government services in various contexts. However, there is a lack of research that examines the perceived barriers to B2G e-commerce adoption and develops an understanding of cause and effect group variables among them. This research is the first of its kind to extensively review the relevant literature in e-commerce adoption and assess the selected key factors which are equally relevant in the B2G e-commerce adoption. The authors apply a unique multi-criteria decision-making technique called DEMATEL to understand the nature of the barriers and collect data from eight experts having experience in B2G procurement in the public sector and government organizations. The data findings revealed that out of nine selected variables, five (i.e., lack of IT infrastructure [B1], lack of expertise and technical skills [B2], high cost of technology [B3], perceived information security risk [B5], and lack of awareness of government issues and legal policies [B6]) belonged to the ‘cause group' whereas the remaining four (i.e., organisational resistance to change [B4], lack of top management support [B7], low perceived operational benefits [B8], and unwillingness to adopt B2G e-commerce services [B9]) were found to be part of ‘effect group'. The theoretical and practical implications of the current study may enhance the understanding of B2G e-commerce adoption.