This article is available open access through the publisher’s website at the link below. Copyright @ 2011 The Author.This article challenges a received wisdom in the liberal peace thesis, namely that the roots of the conjunction of liberalism and peace can be traced back to the idea of an essentially pacific commercial civil society in the 18th-century Scottish Enlightenment. The article instead shows that the Scottish Enlightenment was committed to the idea of military virtue. Textual analysis of the work of Adam Smith and Adam Ferguson reveals a deep and abiding commitment to martial values. The article explores this commitment via an account of the rise of concerns over ‘effeminacy’ in the 18th century, understood as a threat to both military virtue and masculine strength. In exploring these ideas the article claims that IR has helped perpetuate one of today’s key political myths: that liberalism is committed to peace.