In this study, the integration of ICT into educational activities by vocational high school teachers was described within the scope of school directors, students and ICT tools. In the study which was designed as a holistic single case one, activity systems theory was used as a unit of analysis. The data was collected through observation, semi-structured interviews and questionnaires in the study which was carried out on four teachers, 106 high school students and 1 school director. The data obtained in this study was analyzed within the framework of affecting factors taken from the activity system. The subject, community and tools were analyzed within the scope of activity system. It was found in the study that teachers implemented the integration of ICT into instructional activities as the only member of the process. It was also found in the study that other stakeholders did not fulfil their roles, and what is worse is that they were not aware of their roles. Besides, it was found that ICT integration practices were found to differ among teachers.