The Elaboration Likelihood Model (ELM) is one of the most fundamental models for predicting attitude changes and is widely applied in persuasion research. As a dual-process theory, the ELM models two routes of processing persuasive messages: It distinguishes between the central route with strong elaboration and the peripheral route with weak elaboration. The strength of elaboration, in turn, has consequences for induced attitude changes. In their 1986 article, ‘The Elaboration Likelihood Model of Persuasion’, Richard E. Petty and John T. Cacioppo presented the model’s seven key postulates and supported them with numerous empirical studies. The ELM originated in social psychology and has been a central concept for explaining changes in attitudes depending on the message, the recipient, and the reception situation for around 40 years. This article provides an overview of the original article and relates it to the authors’ other works. It also discusses the model’s impact and the criticism it has received.