<p>Due to their versatility, biocompatibility and high transconductance, organic electrochemical transistors (OECTs) have become the subject of interest in a wide range of research areas. To transfer this promising technology from the research laboratory to real-world applications, it is essential to understand underlying processes governing the performance of these devices. Developing models that capture the nature of the complex electrochemical processes allows to optimize devices and materials efficiently and expediently, driving research forward. This article aims to summarize recent developments in the modeling of OECTs, focusing on thermodynamic and drift–diffusion models, as these models can provide an in-depth look at the underlying physical processes driving the outstanding device properties of OECTs.</p> Graphical abstract <p></p>