The implementation of socially sustainable practices in suppliers situated in challenging institutional contexts is examined using institutional theory, both in terms of how institutional pressures affect implementation and what explains the decoupling of practices from the day-to-day reality. A multi-case study approach is employed based on seven apparel industry suppliers in Bangladesh. Cross-case analysis highlights the coercive, mimetic, and normative pressures on suppliers to implement socially sustainable practices. A key pressure identified that has not previously been highlighted in the literature (...) is horizontal collaboration between buyers, which intensifies coercive pressure on suppliers and increases the consequences of non-compliance. The factors that contribute to decoupling are categorized into firm-, supply chain-, and environment-related factors. Further, six propositions are developed on how specific forms of institutional pressure can tackle particular decoupling factors to support implementation. The paper responds to recent calls for greater scrutiny of why and how firms decouple ethical practices and supports the development of the literature specifically on social sustainability, which lags behind that on environmental sustainability and has been largely focused on the Western buyer perspective. The findings have implications for the diffusion of ethical practices into supply chains, especially distant suppliers in very different and challenging institutional contexts. (shrink)