“Is it fair to be dismissed for social media activity, and are there any limitations to the employer’s managerial prerogative? These are the questions that this article addresses by examining the compatibility of discipline or dismissal with human rights law, with a primary focus on United Kingdom (UK) and European human rights law. It argues that UK courts and tribunals erroneously accept the lawfulness of such dismissals most of the time. This is due both to weaknesses in the English law of unfair dismissal, and to courts’ and tribunals’ limited engagement with human rights at work. Technical aspects of social media usage, with which courts and tribunals are often unfamiliar, add a further layer of complexity. Two factors make dismissals for social media activity particularly challenging for courts: first, the fact that social media are online platforms that everyone can potentially access, and hence public rather than private space; second, that expression on social media, often spontaneous and thoughtless, is not viewed as a particularly valuable form of speech. The argument of the article is that both the right to private life and the right to free speech are implicated in dismissals for social media activity, and that they should be viewed as lawful in very limited occasions, for employers should not have the right to censor the moral, political and other views and preferences of their employees even if it causes business harm.”