This thesis focuses on a deeper understanding of different aspects of the effects of home country institutions on the firm internationalization process of mature entrepreneurial firms. It is composed by a bibliometric review of the literature on international entrepreneurship that uses institutional theory, covering the period between 2008 and 2020, and two in-depth longitudinal case studies. In the bibliometric review, a total of 65 articles were selected. The analysis proceeded in two steps. First, a descriptive analysis was performed to characterize the papers in terms of their nature and content. Second, the bibliographic coupling technique, using the VOS Viewer software, was employed to identify theoretical trends in the field. The 13-year period was divided into three periods of four years. The empirical part of this thesis consists of two case studies. The two separate cases helped to achieve a deeper understanding of different aspects of the effects of home country institutions on the firm internationalization process of mature entrepreneurial firms.