Educational technology is an up-date concept that teachers use in their educathion and training activities both inside and outside the classroom. This research was conducted to determine the mental models of secondary school teachers regarding the concept of educational technology. The research which was carried out in the spring term of the 2017-2018 academic year was prepared with the participation of a total of 40 secondary school teachers. In the research, a single case study design was used in the qualitative research model and an independent word association test was used in data collection. The data obtained were arranged according to content analysis. At the end of the research, the mental models of secondary school teachers related to the concept of educational technology consisted of words and sentences that they stated about the concept of educational technology. The data are concentrated under the relevant categories. It has been determined that the mental models of secondary school teachers regarding the concept of educational technology are concentrated in the categories of technological products of educational technology and definition of educational technology. In addition, it has been determined that secondary school teachers have alternative concepts and cognitive deficiencies in many categories related to the concept of educational technology. At the end of the research, suggestions on the subject were presented.