The article discusses selected theoretical approaches to early internationalizing companies (EIC). These approaches deal with the key internal and external determinants of the early and quick internationalization of small and medium-sized companies. Most of the models discussed by the author refer to the concept of international entrepreneurship. The personal characteristics of the founder/first owner of a company are a key factor in the models discussed, the author says. The author uses descriptive and comparative methods in the article. The models presented include six major theoretical approaches to early internationalizing companies, developed in economically advanced countries by Madsen and Servais; Rasmussan, Madsen and Evangelista; Rialp, Rialp and Knight; Mainela, Pernu and Puhakka; Andersson; and Evers. There is also a seventh approach developed by two Polish authors, Cieślik and Kaciak, who highlight the links between the early internationalization of companies and international entrepreneurship as well as economic reforms in postcommunist countries in Central and Eastern Europe. The article also aims to predict future directions of research into EIC.