Mediatization is nowadays considered an influential theory explaining societal, political, and cultural alterations driven by media technologies. Mediatization research, initiated almost 20 years ago (with its precursory ideas placed in the first half of the 20th century), witnesses at present dynamic theoretical, methodological, and empirical developments, obtaining a status as one of the most essential and ambitious research fields within the social sciences. Mediatization theory deals with (meta)process in which media communication is becoming increasingly complex, takes place more often, covers a growing number of topics, and lasts longer. The goal of this study is to contribute to our understanding of mediatization as well as to make the theory more familiar to non‐media scholars by presenting the state of the art and the most promising research lines of scientific inquiry. Starting from conceptualization and operationalization, we also aim to sketch the dimensions, fields, and forms of mediatization as well as to present examples of different domains where mediatization is most advanced, that is, mediatization of culture, society, and politics, or most promising, that is, mediatization of journalism.