Upper secondary education in Sweden involves around 98 percent of 16-18 year old adolescents. Among these 55 percent attend vocational training programs. To meet changing demands on the labour market caused by technological development and structural reorientation, the educational system has to adjust to these new circumstances by reorientation in education methods, action target (i.e. learning in working settings) which will eventually improve the quality in education and the pupils/students employability. This reorientation concerns particularly vocational-oriented schools. To improve the quality of upper secondary vocational education, the Swedish National Agency for School Improvement started a two year project in 2006 with the aim of encouraging upper secondary schools to form networks with other schools and through these spread and share experiences and ideas about school improvement, working methods and organisation. Behind the project there was a vision encouraging other school organisations to learn how to improve quality in education by the experiences of previously successful local projects.Empirical data have been collected through interviews with some of the schools in the project and a questionnaire has been handed out to all of the schools. Data also include newsletters and minutes (covering meetings) received from the networks as well as documents concerning how and why these ideas originally was formulated by the Swedish National Agency for School Improvement.The aim of the paper is to analyse the process of diffusion of knowledge about school improvement in these networks.