Relationship marketing managers around the world actively try to stimulate customer engagement because of its performance-enhancing effects. Research insights into how to engage customers, such that they voluntarily contribute their resources to support companies’ marketing efforts, almost exclusively pertain to individual, domestic markets. However, the prerequisites of customer engagement strategies naturally differ across country-specific market environments. Therefore, the authors develop a conceptual, comprehensive battery of cultural, institutional, societal, and economic country-level contingency factors (CISE indicators) as well as between-country psychic distances on those indicators. A set of 11 high-level research propositions aims to enhance marketing researchers’ and managers’ understanding of the contingencies of international customer engagement strategy effectiveness and customer engagement's performance ramifications. The analysis reflects the richness and complexity of potential contingency effects across the four CISE categories and encourages empirical research on their separate and joint effects.