The chapter provides a novel theoretical framework for the analysis of competitiveness, solidarity, and their relationship. A comprehensive analysis of the fortune, conceptual history, and meaning of the terms competitiveness and solidarity shows that, while the latter has different but complementary meanings, the former has three independent and contradictory faces: competition, relative performance, absolute performance. This fact has important repercussions on the relationship between competitiveness and solidarity, which can be conceptualised in a variety of different ways: as antagonistic, as mutually reinforcing, and even as coinciding. An awareness of this conceptual complexity is essential both for theoretical research and for empirical and policy-oriented analysis.