This article has seven parts. In the first part, an introduction to the semantic approach is offered. The second part deals with the differences between syntactic and semantic approaches to the structure of scientific theories. In the semantic approach, models play a pivotal role in theorizing, and scientific theories are not more than a set of models. The idea that scientific theories contribute to understanding the world entails that models are the entities that do this job. Therefore, the third part attempts to provide an overview of the role of models in scientific theories and the next part deals with two main branches of semantic approach: structuralism, and state space approach. The fifth part focuses on the view that some philosophers like Suppe and Giere offer realistic interpretation of this approach. Some of the most famous criticisms of semantic approach are discussed in the sixth part and the last part is concerned with some alternative approaches.
)