In this thesis, we enquire into the application of ICT in connection with collaboration and knowledge sharing among teachers at a gymnasium – a subject especially relevant with regards to the gymnasium reform agreement. The gymnasium reform agreement which became effective in August 2005 has triggered considerable changes in gymnasium education – changes of academic, educational and organizational nature. Today, the Ministry of Education demands that teachers at gymnasiums share knowledge and experiences and communicate and collaborate on the course of education and educational material. Previously, co-operation among teachers have been limited to short dialogues, and educational materials have been the responsibility of the individual teacher. Therefore, the practice of the teachers has been characterized by considerable independence as individual teachers have primarily used their own educational materials. The gymnasium reform agreement, on the other hand, focuses on the interaction between gymnasium educations in which relations and interaction among the teachers and the subjects they represent are emphasized. As a consequence the last few years have presented teachers with radical changes to their daily work, examples of this being the need to familiarize themselves with the schools' information technology systems, and the demand for transforming the visions for gymnasiums laid out by the Ministry of Education, into practice. The demand for collaboration and renewal in the education, therefore, creates frustration for many teachers as it requires them to rearrange previous practice. Taking this as our basis, we deal with how knowledge sharing works in practice at selected gymnasiums, and how school information technology systems may promote collaboration and knowledge sharing among academic teachers in relation to the development of their educational practice. The three gymnasiums with which we cooperate are Aalborg Handelsskole, Aalborghus Gymnasium and Aalborg Tekniske Gymnasium (Aalborg Gymnasium of Commerce, Aalborghus Gymnasium and Aalborg Gymnasium of Technology). Although culturally different, the three schools are of similar appearance, and stand before similar problems and needs following the gymnasium reform agreement. The purpose of involving three culturally different schools is to create an understanding across the schools, as solutions implemented at one school may not exist at others. To the extent that the schools' collaboration and knowledge sharing system can solve the same problem, the schools will be able to learn from each other. The schools information technology systems can promote such a practice, as they allow dialogue between teachers to be saved for the benefit of other teachers, among other things. Therefore, we also deal with the question of how such a system may be designed, which demands have to be met, and what the conditions are for collaboration and knowledge sharing among academic teachers. This may be divided into systems and users. The current information technology systems on the schools fulfil many of the needs of the teachers. For this reason the schools do not need a revolutionary new information technology system. On the other hand, changes in the culture and attitude among the teachers are difficult to ignore, and there are many barriers to overcome in this area, given that the teachers have not previously had a tradition for collaboration and knowledge sharing to the extent now expected of them. Our empirical data from three schools suggest a tendency towards a focus on the system. However, focusing on the users is just as important.