According to Agenda 21, the United Nation's action plan for sustainable development, "Governments and private sector organisations should promote more positive attitudes towards sustainable consumption through education, public awareness programmes and other means". But some could wonder whether the cultivation of frugal consumption habits in schools is compatible with basic liberal principles. This article argues that, in societies like ours, liberal egalitarian theories of justice should permit and even advocate teaching frugality in educational institutions. Liberal egalitarianism expects educational institutions to equip children with the abilities and virtues needed to live well by their own judgment and in compliance with just institutions. The article examines how frugality could be one of these virtues. First, frugality is conducive to better compliance with our distributive obligations towards the current poor and future generations. Second, frugality enables prospective adults to live well with their fair share of scarce resources, and even with less. Third, frugality increases autonomy and facilitates its exercise. The article thus concludes that liberal egalitarian institutions should encourage schools to teach frugality.