This article argues that Internet censorship is more fragile than is generally supposed and is, in fact, vulnerable to abrupt collapse. The volume and rapidity of online communication renders perfect policing of the Internet technologically impossible. Authoritarian governments are thus forced to rely on Internet users to police themselves in the form of self-censorship. This strategy has proven largely successful—legal ambiguity regarding what constitutes impermissible speech fosters norms of self-censorship. This reliance on self-censorship, however, renders these censorial systems susceptible to shocks. We set out a model that explains sudden breakdowns in Internet censorship that we term “cyberspeech cascades.” A cyberspeech cascade occurs when small expressions of online dissent produce large shifts in public perception regarding the acceptable limits of online expression that are, in fact, inaccurate. Online bandwagons of progressively more brazen speech proliferate into large-scale torrents of uncensored expression, triggering the temporary collapse of self-censorship norms online.