Internationalization as a concept and strategic agenda is a relatively new, broad, and varied phenomenon in tertiary education. During the past half-century, internationalization has evolved from a marginal activity to a key aspect of the reform agenda. This analysis addresses the following points: What are the historical developments of internationalization? What do we mean by internationalization? What are the key factors in international tertiary education that impact, and are impacted by, this phenomenon? What initiatives and policies are developed to enhance the internationalization of tertiary education? What are the key data, trends, and challenges that are crucial for the future of internationalization, abroad and at home, in a critical time of transformation as a result of nationalist-populist developments, climate change and the COVID-19 pandemic?