Developments in information and communication technologies (ICTs) offer new opportunities for enhancing citizen interaction with government and engagement in public policy-making, providing potential to expand the scope, breadth and depth of government consultations with citizens and other key stakeholders. However, ICTs can also pose significant challenges to governments in terms of their technical, political and constitutional implications. This publication highlights policy lessons in using ICTs to promote public participation in policy-making, drawing on examples of current practice from 12 OECD member countries (Australia, Canada, the Czech Republic, Finland, Germany, Italy, Mexico, the Netherlands, New Zealand, the Slovak Republic, Sweden and the UK) as well as the European Commission. It suggests ten guiding principles for successful online consultation, and identifies five key challenges for online citizen engagement in policy-making.