In this paper, factors that effect on ICT adoption by SMEs in Tehran (Iran) are investigated. To do so, after reviewing the literature, we identified the factors affecting ICT adoption by SMEs in Tehran and, based on this review, we proposed our hypotheses. Factors include internal factors, external factors and ICT specifications that influence on IT adoption by SMEs. All hypotheses are confirmed except the one that articulates the relationship between perceived ease of use and ICT adoption by SMEs. Weak managerial support, lack of available skills, weak strategic vision regarding the ICT, weak innovative environment and insufficient financial resources are among the internal barriers. External barriers include weak governmental supports, legal environment, low cultural acceptance and weak pressures from customers, suppliers and competitors. Finally, low perceived usefulness and compatibility are among the ICT specifications that limit ICT adoption by SMEs.
