The paper reviews mobile government (m-Government) adoption and diffusion factors in developed and developing economies. m-Government is viewed as a class of e-Government applications and refers to any transaction via mobile technologies, such as laptops, phones or personal digital assistants (PDAs). The most significant features of mobile technology include mobility and portability. The ubiquitous dimension of mobile technologies provides means of accessing services anywhere, anytime, and on the move, thanks to advanced wireless interface technologies. The paper examines the literature base in respect of known obstacles to the adoption and diffusion of m-Government, drawing the distinction between technical and non-technical barriers. Furthermore, the paper discusses the economic impacts achieved by e-Government in many countries following the transfer of public services to electronic services; some examples are given from the developed and developing countries.