Civil society organisations (CSOs) and social movements have been instrumental in the progress made towards holding transnational corporations responsible for violations of human rights and environmental degradation, particularly in global value chains. Increasingly, CSOs have also been advocating for binding obligations within the regime of business and human rights nationally, regionally as well as internationally. This chapter examines the mobilisation of civil society in Germany and Luxembourg for the adoption of mandatory human rights due diligence (mHRDD) laws. Arguably, both the French Loi de Vigilance adopted in 2017 as well as the German Lieferkettengesetz (LkSG) adopted in 2021 were the result of widespread mobilisation from below that assembled a variety of organisations and professional groups, including NGOs, trade unions, epistemic communities, and church-based initiatives. While Luxembourg has not yet enacted an mHRDD law, CSOs succeeded in putting an initial legislative proposal on the government’s agenda in 2023. The chapter critically analyses how such national coalitions for mHRDD laws cooperate across borders, borrowing and adapting activist tactics and discursive frameworks employed by their counterparts to agitate for more responsible business conduct.