Relationship marketing is central to cross-border business-to-business (B2B) exchange because international transactions amplify uncertainty, information asymmetry, and coordination costs. When buyers and suppliers operate across institutional regimes, legal systems, cultures, and time zones, relational mechanisms—trust, commitment, communication, and joint problem solving—often become as important as price and product performance. This paper develops an integrative conceptual framework for relationship marketing in cross-border B2B markets by synthesizing the commitment–trust theory, transaction cost economics, resource-based and relational views, network theory, and institutional theory. We explain how relationship governance complements or substitutes contractual governance, how distance and complexity reshape relational processes, and how digitalization changes interaction patterns and value co-creation. We propose a multi-level model linking antecedents (distance, dependence, uncertainty, cultural intelligence, and interorganizational capabilities) to relationship processes (communication quality, adaptations, fairness, knowledge sharing, and conflict management) and outcomes (performance, innovation, resilience, and relationship continuity). Managerial guidance is offered for designing relationship portfolios, aligning incentives, building cross-border key account management (KAM) systems, and measuring relational health using leading indicators. The paper concludes with research propositions and an agenda for future empirical work in digitally mediated, multi-stakeholder B2B networks.