[영문]This paper considers what we might expect to be the effect on social policy of Turkish accession to the EU by reviewing the impact of EU membership on social policy in other new member and candidate countries. This effect begins long before membership is finalised, and continues long after membership has been achieved. The patterns of impact can be divided along a number of dimensions: between ‘accession’ and ‘enlargement’; state and civil society; centre and periphery; formal and substantive; and different welfare institutions. In the course of reviewing these variations, the paper reflects upon the nature of social policy itself, and in particular the nature of the European Social Model.