The article reviews key theoretical concepts and empirical studies on the relationship between early internationalization and company performance. The author uses descriptive and comparative methods in the article. The paper discusses an array of theoretical arguments for a positive and negative internationalization-performance relationship. The key theoretical concepts related to the costs of firm internationalization are presented. The author identifies different categories of internationalization costs that affect firm performance. Witek-Hajduk also highlights theoretically derived and empirically shown relationships between the degree of internationalization and firm performance. Moreover, the article discuses the results of several empirical studies conducted in highly developed countries on the relationship between early internationalization and firm performance. According to these empirical studies, early internationalization has a positive impact on firm performance. The author highlights a research gap: there is a lack of empirical studies on the relationship between early internationalization and the performance of Polish firms and companies from other emerging markets.