The disaggregation and geographic dispersion of global value chains (GVCs) have expanded the responsibility of international buyers from firm-level corporate social responsibility (CSR) towards social sustainability of their emerging country suppliers. We theorize, in this paper, that the effectiveness of lead firms’ GVC governance strategies for social sustainability—which can be audit-based or cooperation-based—depends on the local institutional context of the supplier. Supplier country institutions exert legal and civil society pressures for social sustainability, which shape suppliers’ attitude and receptiveness towards lead (...) firm requests. Using unique primary data from 356 garment and footwear suppliers in 11 emerging countries, which supply to Western European or North American buyers, we show that GVC governance strategies are particularly effective for suppliers’ social sustainability implementation when there is ‘contextual fit’ with local institutional pressures for social sustainability in the supplier country. Our study identifies the boundary conditions of GVC governance modes, and demonstrates a complementary relationship between organizational arrangements and their institutional-level counterparts in the context of social sustainability. (shrink)