Cross-border agri-food supply chains are increasingly facing institutional uncertainty, logistical constraints, and geopolitical disruptions, which increases the importance of supply chain sustainability for the stable development of international trade.

   This study aims to assess how perceived institutional and spatial frictions influence supply chain resilience in the Sino-Kazakhstan agri-food corridor, with particular attention to the mediating roles of relational governance and trust, and flexible strategies.

   The study uses a quantitative approach based on partial least squares (PLS-SEM) structural equation modeling. The empirical basis was based on data from a survey of 100 specialists involved in cross-border agri-food trade between China and Kazakhstan. The results showed that perceived institutional and spatial barriers have a strong positive impact on relational governance and trust (β = 0.502; t = 6.223; p < 0.001), while their direct impact on flexible strategies is not statistically significant at the 5 % level (β = 0.197; t = 1.782; p = 0.075). Mediation analysis confirmed that relational governance and trust significantly mediate the relationship between institutional barriers and supply chain sustainability (β = 0.207; t = 3.978; p < 0.001), whereas the mediating effect of flexible strategies was not confirmed (β = 0.111; t = 1.705; p = 0.088). The findings show that, in the context of cross-border institutional barriers, relational governance is a key mechanism for ensuring sustainability, especially for resource-constrained companies operating in transition economies.