A teacher needs to make choices and decisions that affect what teaching students are exposed to. The school subject of technology is mandatory in Swedish compulsory-level schools (grades 1-9) and is a subject with its own traditions and presumptions. This thesis examines how teachers perceive and shape technology education -their transformation of the subject of technology for teaching. Two aspects of transformation are explored: teachers' attitudes towards technology education and teachers' views of knowledge in technology education.The study employs different research designs in each of the four articles. One study analyses quantitative survey data using statistic methods. One study is based on qualitative data from interviews, and another uses qualitative data from focus groups. These three data-oriented studies recruited teachers teaching technology in Swedish compulsory schools as participants. The fourth article is theoretical in nature and uses philosophical argumentation and reasoning to develop a framework for researching knowledge in technology education.The results contribute to our understanding of teachers' attitudes towards technology education -attitudes may look different and be affected by different variables. Another result is a framework for technology education based on knowledge traditions, which can be used in research or in teaching. The research also contributes new understandings about how teachers talk about knowledge in technology education, showing that teachers have a broad view of knowledge that includes more than what is included in the framework for technology education. The overall results identify several aspects of teachers' transformation of the subject of technology. Some of these aspects pertain to the teachers themselves, such as their knowledge and attitudes. Others regard aspects external to teachers, such as time-related aspects and school culture and traditions. Teachers' choices, goals and purposes are significant for how they transform technology into teaching practices. In seeking to move from the results of my research towards its implications, I discuss the awareness of transformation. By being aware that teaching involves transformation, and by being aware of the different aspects that affect this transformation, school and university stakeholders can contribute to the development of technology education. Being aware of the transformations involved in teaching may make it easier for teachers to stay focused on the goals and content of the subject of technology.