With the increase in environmental and social challenges resulting from development, competition between countries on the international stage is becoming particularly important and should be more responsible and sustainable. In this context, the question arises as to the level of sustainable competitiveness of the European Union (EU) in the context of the outermost regions (OR), which will be the research problem addressed in this article. In the context of the above, the aim of this article is: (1) to discuss the concept of sustainable competitiveness in theoretical terms; (2) to present the level of sustainable competitiveness and its pillars in the countries of the European Union, with particular emphasis on France, Spain, Portugal, Cyprus, and Malta; (3) to present the specific characteristics and main development challenges of the OR (4) to identify the main assets – strengths of the ORs that could contribute to strengthening the sustainable competitiveness of the EU. The analysis has shown that the EU is a global leader in sustainable competitiveness, although the level of this competitiveness varies greatly between Member States, which is a consequence of, among other things, differences in the level of economic and social development, the structures of their economies, and their approaches to implementing the tasks of the European Green Deal. The analysis has also identified the potential strengths of the ORs that could strengthen the EU's sustainable competitiveness in the long term.