Stereotypes were introduced into the Unified Modeling Language to provide means of customizing this general purpose modeling language for its usage in specific application domains. The primary role of stereotypes is to brand an existing model element with specific semantics, but stereotypes can also be used to provide means of a secondary classification of modeling elements. This paper elaborates on the influence of stereotypes on the comprehension of models. The paper describes a set of controlled experiments performed in academia and industry which were aimed at evaluating the role of stereotypes in improving comprehension of UML models. The results of the experiments show that stereotypes play a significant role in the comprehension of models and the improvement achieved both by students and industry professionals.