Effective implementation of Information and Communication Technologies (ICT) plays an important role in school education, especially in a developing country like India, to improve the quality of education. School teachers' lack of confidence and motivation for using ICT is one of the major barriers of its implementation in schools. These barriers can be either nonmanipulative (i.e. which cannot be changed) or manipulative (i.e. which can be changed with the help of school/government policies). This paper studies the impact of non-manipulative and manipulative teachers' factors on their perceived proficiency in using ICT in the classrooms. It uses the primary data of 515 school teachers from the Maharashtra region of India teaching at high-school level (8th grade to 12th grade). The study concludes that both non-manipulative as well as manipulative teachers' factors are important in affecting teachers' perception regarding their own proficiency in using ICT in the classrooms. The study also provides some suggestions to improve the perception by changing some manipulative factors.