The widespread diffusion of the Internet globally has prompted most retail banks to offer Internet banking services. A recent study in Singapore identified attitudinal and perceived behavioral control factors as having an influence on consumer adoption of Internet banking. It is expected that the national environment will also impact this process. The aim of this study, therefore, was to replicate the Singapore study in South Africa, compare the results between the two countries, and explain differences in adoption process in terms of the national environment. The results confirm that attitudinal and perceived behavioral control factors influence adoption in South Africa as in Singapore, but with differences in the number of determinants and the degree of influence of certain determinants. These differences were explained in terms of three environmental dimensions: socio-economic conditions, the state of Internet diffusion, and government information and communication technology (ICT) policies, respectively.