The intersectionality approach has been the central framework for understanding gender-based discrimination since the 1990s and remains relevant today, used in every relevant feminist analysis and crucial for feminist activism. Intersectionality has emerged as feminism’s key overarching analytical and political tool and thus is the primary focus of this chapter. The first part provides introductory notes on the genesis of feminist streams of thought and practice, aiming to demonstrate how they contributed to the development of the intersectional approach to gender-based discrimination. It discusses converging trends that facilitated the emergence of the intersectional feminist perspective/s. Special attention is paid to the dialectic of patriarchy and emancipation within discussions on converging feminist ideas, because the author believes that any discussion of patriarchy (and its intersecting with other forms of discrimination) in contemporary times must always be placed within the context of this dialectic. It also considers tendencies of divergence and conflicts among contemporary feminist movements, which jeopardize and can put under threat the feminist legacy and its survival. The examination of converging and diverging phenomena serves as a preparatory phase for a subsequent exploration of intersectionality as both an analytical tool and a political tool. The second/central part is devoted to the meaning, manifestations, and implications of intersectionality and the diversity approach in feminist theory and practice. It focuses on the above-mentioned analysis of intersectionality as an analytical and a political tool for a feminist reconsideration of multiple gender-based discrimination. The third part is devoted to feminist political theories of gender justice, whilst the fourth part is dedicated to the feminist legal theory of substantive gender equality, both of which, in the author’s opinion, represent unavoidable, complementary aspects of the intersectional approach to gender-based discrimination. The conclusion summarizes the connections between political theories of intersectionality and diversity, political theories of gender justice, and the legal theory of substantive gender equality within the feminist intersectionality approach.