Educational technology can be defined as the study and ethical practice of facilitating learning and improving performance by creating, using and managing suitable technological processes and resources. The technology utilizes both educational system and physical hardware. It involves several domains including theoretical learning, computer-based training, web-based learning, etc. Corporates, nations and individuals adopt each evolving technology, only if, it adds value. To recognize the value of such technology, it is essential to be familiar with the technology adoption process and factors affecting it. Well established proven models explain the factors in adoption process. In this paper, the sources, technologies and delivery methods of ICT in Educational Institutions, have been discussed. Six significant models (one model from each decade 1960-1970, 1970-1980, 1980-1990, 1990-2000, 2000-2010 and 2010-2020) have also been discussed for adoption of evolving technologies in Educational Institutions.