The significance of information technology in education is usually assessed or evaluated on terms of some measures of effectiveness. In different school settings the effectiveness is operationalized in different ways, and in the literature various methods of determining the effectiveness have been discussed (e.g., Secretary's Conference on Educational Technology 1999). In this article, models for assessing the significance of information technology in education based on the teachers' subjective perspective are introduced. Theoretical backgrounds of the models are based on methods developed in information management science to assess the impact of information technology (IT) in industry and business. The first model is comprised of categorizing the rationales for using IT in education, the second model assesses the strategic impact of existing IT applications on one hand and of future IT applications on the other on education, and the third model assesses the roles of applications of IT in teaching. Also, the empirical findings of a small scale test of the two latter models in the Teacher Training School in Rauma (TTSR), a primary school in Finland with about 260 pupils and 19 teachers, are introduced.