The European Union (EU) played an instrumental role in re‐starting the international development policies in central and eastern European Member States, but questions remain about how far this policy area has been Europeanized since accession. Focusing on the Czech Republic, Hungary, Poland and Slovakia, this article investigates why the new donors have been reluctant to adopt the EU's development acquis more fully. The article traces the socialization processes offered by the EU's development policy rule‐making and subsequent national rule implementation. The conclusions reveal three reasons why socialization has been weak: perceptions among the new Member States on the procedural legitimacy of the development acquis; low domestic resonance with the development acquis; and inconsistencies in the activities of norm entrepreneurs. The article contributes to our understanding of development policy in the EU – particularly how decision‐making takes place within the Council and its working groups post‐enlargement.