This study examines the voluminous case law of the European Court of Human Rights relating to freedom of expression and defamation. It starts by clarifying the concept of defamation and positioning it in relation to freedom of expression and public debate. It explains how defamation laws that are overly protective of reputational interests and that provide for far-reaching remedies or sanctions can have a chilling effect on freedom of expression and public debate. The principle of proportionality in respect of defamation laws and their application is therefore very important when it comes to preventing such a chilling effect.