Hypatia will bring about lasting change in the way schools, science museums, research institutions and industry engage teenage girls in STEM across Europe. Bringing these stakeholders together with gender experts and teenagers themselves, Hypatia will develop, pilot and disseminate a unique modular toolkit of activities and guidelines for engaging teenagers in STEM in a gender-inclusive way. These innovative activities, based on existing European good practices, will be implemented in 14 EU countries and further afield, in schools, science museums and by institutions in research and industry, thanks to hubs of stakeholders strengthened through the project. The activities will have a central focus on gender-inclusive ways of communicating STEM, empowering teenage girls and exploring the range of skills that are needed for the great variety of STEM studies and careers open to young people. The Hypatia hubs will provide a sustainable basis for these activities to be carried out on the long term, with a focus on dissemination through networks and stakeholder engagement allowing the project impact to multiply.