Girls are increasingly visible as activists demanding social change, equity and justice. Yet communication between girls and policymakers is fraught with challenges over how to translate young people’s knowledge into policy change. This article traces the history of the manifesto as a form for the marginalized to articulate new social visions, drawing on the Riot grrrl manifestos as examples of this genre. It describes the creation of the first Girlfesto at the 2018 Circles Within Circles event that brought together girls, young people, activists, researchers, and policymakers from six countries in the Global North and South to consider the role of community art-based activism by girls and young people in challenging gender-based violence, concentrating on colonial systems of violence against indigenous women and girls in Canada and South Africa. We analyse the Montebello Girlfesto and the opportunities and challenges in using the Girlfesto model, with reflections from girl participants.