This country report analyses the salience and position of differentiated integration (DI) in Portugal in the period between 2004-2020. Employing a quantitative and a qualitative analysis, it first examines the salience of DI models and mechanisms for the successive Portuguese governments using documents such as government programmes, Prime-Minister speeches, parliamentary debates, and statements by the Prime Minister in European Council meetings. Secondly, it reviews governments’ general positions on DI, while zooming in on four peaks of salience: the Lisbon Treaty, the debate on the Unitary Patent, the financial crisis and the discussions on the Financial Transaction Tax and the Fiscal Compact, and the White Paper on the Future of Europe. The results from the salience analysis demonstrate a low saliency of differentiated integration (DI) and, more generally, European integration in Portugal. DI models were more salient than DI mechanisms, while DI instances are the most salient. Salience was enhanced by an increasing intersection between domestic and European politics during the euro crisis period, politicising the debate especially around DI instances of an economic nature. The position of Portuguese governments regarding DI during the period analysed was overwhelmingly negative. In general, this stance was also shared by the opposition parties. Over the period of analysis, a wide consensus stood out among Portuguese political parties that DI models clearly go against both the European – by risking a disaggregation of the EU – and the national interest – by possibly pushing Portugal into an even more peripheral position. Notwithstanding this generally negative view of DI, mainstream parties – which alternated in government during the timeframe of the analysis – viewed the enhanced co-operation mechanism in a generally positive manner, recognising its potential to promote advances in European integration when the EU faced critical deadlocks.