This chapter demonstrates and extensively discusses the process of ICT diffusion across 36 Asian economies between 1980 and 2015. It provides a detailed analysis of country-specific ICT diffusion patterns in selected Asian countries, and with this aim we use four ICT indicators extracted exclusively from the World Telecommunication/ICT Indicators database 2016 (20th Edition). These indicators include the following: Mobile-cellular telephone subscriptions per 100 inhab., Fixed-broadband subscriptions per 100 inhab., Active mobile-broadband subscriptions per 100 inhab., and share of population using Internet. It extensively analyzes the process of ICT diffusion and to meet this goal we apply a logistic model and estimate elementary characteristics of the process of diffusion for each country individually. Additionally, the chapter examines technology substitution effects regarding fixed-telephone lines versus mobile-cellular telephony, and fixed-Internet networks versus wireless-broadband networks.