Governments sometimes adopt policies that are not aligned with their preferences or have not come onto their agendas when doing so is linked to a reward. International organizations can therefore set conditions for coveted membership that include adopting new human rights and regulatory policies. As international organizations increasingly converge around the UN Guiding Principles on Business and Human Rights, how might they promote national uptake of these guidelines? This article considers the prospects of accession conditionality in answering this question. The focus of the article is on European Union and Organization for Economic Cooperation and Development (OECD) expansion in Central and Eastern Europe, where uptake of business and human rights policies remains comparatively low. The article argues that while these organizations increasingly include business and human rights conditionalities in accession negotiations, there remains significantly greater scope for promoting the Guiding Principles.