In the context of a reshaping world order, this study analyzes and proposes a strategic cooperation model between Vietnam and Russia within the framework of Expanded South–South Cooperation, aligned with Vietnam’s new era development agenda and contemporary trends in international collaboration. Employing a historical–policy analysis combined with a case study approach, the research draws on official documents, scholarly literature, and international reports to assess Vietnam–Russia relations across historical stages, key cooperation pillars, and opportunities for expansion into emerging sectors. Findings indicate that the relationship is underpinned by high strategic trust, stable mechanisms, and significant potential in renewable energy, high technology, digital economy, and cultural diplomacy. The proposed model outlines five guiding principles, a multi-tier cooperation structure, priority sectors, and actionable policy recommendations, thereby expanding the concept of South–South Cooperation by integrating global strategic partners such as Russia.