Aspects of internationalization found widespread interest in academic research. However, research attention has largely focussed on prominent large firms. Compared to research on multinational enterprises the state of knowledge about the internationalization of entrepreneurial companies is limited so far. In order to contribute to research in this particular field, the dissertation focuses on an empirical examination of the internationalization process of early internationalizing firms. This phenomenon of young firms venturing into foreign market right from inception raises several questions: How is it possible that young firms venture into foreign markets and manage to cope with the challenges of internationalization at such an early stage in their life cycles? How are young firms able to learn how to handle the liabilities of foreignness before and after foreign market entry? How does an early internationalization behavior impact the performance of the firm? Elaborating on these research questions, the overall aim of this work is to contribute to a deeper understanding of the internationalization process of early internationalizing firms by studying the driving forces of this phenomenon, the learning behavior of early internationalizing firms and the effects on the firms¿ performance using different theoretical and methodological approaches.