This PhD project has the overall goal of identifying persuasive discourse strategies within a range of public smoking cessation sites online in the UK. It aims to contribute to linguistic theory by looking at how persuasion can be analyzed within an interpersonal pragmatic framework in an online health context, thus dealing with the question of how relational work and identity construction are linked to persuasion. Previous researchers across different fields have highlighted the interpersonal nature of persuasion; however, very few studies have explicitly employed an interpersonal pragmatic approach to analyze persuasion in online health discourse. To operationalize persuasion for a linguistic analysis, Aristotle’s working principles of persuasion are employed. Identity construction and relational work serve as basis to analyze how ethos, logos, pathos are created in these practices. The main corpus consists of 30 public online sources, ranging from peer-to-peer to professional sources. The professional sources are mostly websites, with either a commercial or a governmental background, providing written information to get readers to stop smoking. My analysis focuses on what is regarded as relevant information, the specific ways said information is packaged and how readers are strategically positioned for that purpose. On peer-to-peer sources, people reinforce each other’s conviction to stop smoking by giving each other advice and support. The analysis of online health support groups serves as a counterpoint, indicating what lay people view as their most important concerns and what kind of positions they adopt to successfully motivate each other. To study the aspects of persuasion in depth, three analytical steps are undertaken. A thematic analysis of the entire corpus allows me to identify the most common topics, identify clusters of sources and create a sub-sample for in-depth analysis. Second, the sub-sample is exhaustively coded for discursive moves to arrive at the linguistic setup of the practices under scrutiny. Finally, this analysis serves as basis for qualitative close-readings of selected texts to identify the link between linguistic patterns, interpersonal effects and persuasion. This study sheds light on persuasion from different theoretical angle, conducting a linguistic analysis that looks beyond perlocutionarly effects. Further, it gives insight into still under-researched online health practices.