The ISIS “Stein” is a high school in Gavirate (VA), Italy. Around 1400 students attend our school and about 110 teachers work in it. Our school has been participating actively in projects aimed at internationalization, thanks to interchanges with foreign students and schools, stages abroad, Comenius partnerships, CLILL courses abroad, job shadowing projects, projects such as Highlights for High Physics in Italy and SITE Program, CLILL activities in different classes and Physics, Geography and History lessons as a curricular subject in English in a few classes. Our school has aimed at improving the quality of its teaching methodology and internationalization through better teachers. The aims could be summarized as follows: - Provide high quality to international projects linking them to the curricula; - Improve the teachers’ language knowledge in order to cooperate with mother-tongue assistants in curricular activities and future Erasmus+ projects; - manage CLIL projects; - work usefully with non-Italian speakers - Start changes concerning interactivity, modernization and internationalization of the lesson both in L1 and L2,L3 and L4, in order to diminish school leaving; - Develop the staff’s skills in ICT and promote its use both in L1 and foreign languages, as a tool to be used together with more traditional ones. 18 people took part in the project, divided into 3 categories: 1. Teachers and staff members with either little or no knowledge of English (beginners and false beginners). These people attended zero and base courses. 2. Teachers with middle and high knowledge (A2/B1). They attended either language or CLIL courses 3. Teachers of languages (C1 mark of reference). They attended courses on methodology and creative teaching. All the activities of categories 1 and 2 were preceded by preparatory courses of English either in our school or private.