This book offers the first comprehensive philosophical examination of the free speech 'battles' of the last decade, arguing for a critical republican conception of civility as an explanatory and prescriptive solution. Issues such as no-platforming and safe spaces, the increasing influence of Far-Right rhetoric on internet forums, the role of Twitter as a site of activist struggles, and the moral panics that surround ill-judged comments made by public figures, all provide a new set of challenges for society which demand a careful critical analysis. The author proposes a 'republican theory' of free speech, demonstrating how a conception of 'critical' civility, one which combines the importance of expressive respect with the responsibilities of contestation and vigilance, is required if we are to combat some of the most contentious speech-related conflicts facing contemporary society today.