Purpose: The article evaluates the associative relationship between international supervisory board experts and foreign ownership, along with the experts’ influence on the financial and operating performance of firms. The study was based on data collected for 257 companies listed on the Warsaw Stock Exchange in 2010–2015.

Methodology: The dataset was built as a panel, and then generalized least squares regression models with a fixed or random effect were employed to test hypotheses.

Findings: The findings of the study clearly show that the presence of investigated firms in foreign markets positively affects company performance. Moreover, models with dependent variables ROA and ROS show that supervisory board members with foreign experience positively affect profitability indicators of firms that do not operate on foreign markets. The data analyses reveal that international experts are more effective advisors for companies that conduct no business activities on foreign markets. Furthermore, the results show a positive moderate association between the share of international experts in supervisory boards and the share of foreign ownership in the company.

Originality: The article contributes to the understanding of determinants and consequences of the presence of international experts in supervisory boards and company internationalization.