Social media are often referred to as democracy drivers in autocratic states, whereas in some countries, they appear as tools of the regimes that employ a wide range of mechanisms to restrict freedom of expression online. In authoritarian countries, political bloggers stand out as new political leaders or anti-regime actors, serve as alternative information sources, advocate for political action, or mobilize financial support for different initiatives. Political conditions in countries with established governments’ control practices complicate publishing routines for political bloggers and may increase incentives to self-censor. Employing the theory of the spiral of silence, this study analyzes self-censorship in social media among political bloggers in two neighboring post-Soviet autocratic countries - Belarus and Russia. The research is based on a comparison of media legislation in Belarus and Russia, textual analysis of political blogs, and survey among political bloggers in the two countries. The survey demonstrates that political bloggers face obstacles in forms of administrative or criminal sentences, forceful blocking of their pages, online threats, or experience pressure/ attention from secret services. Despite these challenges, political bloggers in Belarus and Russia demonstrate readiness to speak out and criticize political elites. According to the model suggested in this thesis, the majority of political bloggers practice self-censorship at the pre-publishing stages in forms of selecting topics and wording, avoiding particular names. The author argues that in autocratic countries, the spiral of silence, that engages more people to silence their opinion due to political obstacles, can be and is currently challenged by political bloggers, as decentralized political opinion leaders, who aim to break down the spiral of silence. The research contributes to media studies of social media and freedom of expression in autocratic countries. Political bloggers as neither ordinary social media users nor media in the non-democratic world require more attention among media and political scholars.