Rezumat: This descriptive and exploratory study aims to analyse and compare the macro-level determinants of board effectiveness of listed companies for two European countries, the UK and Romania. The main focus is on the relationships between national culture and legal-institutional factors (macro-determinants) and how they might affect board effectiveness in both countries. By investigating the moderating effect of macro-level determinants on board effectiveness, this research contributes to the small number of cross-border studies on board effectiveness in this area. The cross-national context of this study is also relevant against the background of the increasing internationalization of boards. This implies that the understanding of macro-determinants and their effect on board processes becomes increasingly important for boards, and especially chairs, to take into consideration.