The evaluation of the effectiveness of invested funds requires relevant data. This currently applies to investments in all areas of economic activity, including sports. The article’s aim is to determine the factors applicable to the quantification of interest in sports in selected countries. From the perspective of state funding of sports, foreign interest in sports is a part of the mechanism of allocating resources (situated in the Slovak Republic). For businesses, sponsoring sports organizations is a part of their activities connected to the concept of corporate social responsibility and environmental, social, and governance-related indicators. In both cases, it is important to have the necessary background data so that the entities responsible can correctly evaluate the effectiveness and return on such investments. The Czech Republic, Germany, Poland, and Hungary were selected to determine foreign interest in sports. These variables were selected for data analysis to quantify foreign interest in sports: competitions and tournaments, registered athletes, and keyword searches in Google trends. The variables predetermined the methods of data collection and statistical analysis. The main results lead to more accurate data for decision-making on investments in sports. The most popular sports in the given countries based on the interest quantification were identified.