This thesis aims to establish a general theoretical framework for indirect mechanisms of censorship. The law is gradually adopting a broader concept of censorship. However, the current conceptualisations of censorship either lack comprehensiveness or have not established a clear relation between a new conceptualisation of censorship and the existing legal framework of the right to freedom of expression, a shortcoming that this thesis addresses. We ask how we can study and categorise the widest range of censorship mechanisms and aggregate diverse and sometimes conflicting conceptualisations of the term from a primarily legal standpoint. We suggest the dichotomy of direct and indirect censorship as a theoretical basis which is compatible with the existing legal framework of the right to freedom of expression. Adopting an interdisciplinary approach, this thesis extracts a definition of indirect censorship from a legal viewpoint by examining regional and international case law on freedom of expression. It then strengthens the definition by adding, from a sociological viewpoint, an insight on the role of non-legal norms as a means of indirect censorship, which is largely overlooked in the conceptualisations of the term from a legal viewpoint. Based on this definition and using Iran as a case study, we provide an exhaustive catalogue of indirect mechanisms of censorship. The significance of this research is that it informs our understanding of contemporary mechanisms of censorship by providing a general theory of indirect censorship and emphasising the necessity of recognising the growing threat of utilising these mechanisms of covert nature by the regional and international human rights instruments.