Theories of ethnicity are explored, highlighting essentialist representations of culture and the critical deconstruction of these concepts. An overview of the main lines of thought on ethnicity is outlined, with a particular focus on anthropology. The primordialist theory, associated with Clifford Geertz, argues that primordial ethnic ties derive from immediate feelings of affinity based on blood, religion, language, and tradition, characterized by emotional and coercive intensity. Instrumentalist conceptions view ethnicity as a resource used to maximize individual benefits, where ethnic groups are formed to exploit cultural differences for material advantage. Michael Banton analyzes ethnic interactions as competitive exchanges in market situations, influenced by the strength of boundaries between groups. The neo-Marxist perspective considers ethnicity as a reflection of economic antagonisms. Ethnic and racial divisions are functional to the capitalist economic system, segmenting the labor market and perpetuating inequality. Bonacich links tensions between immigrants and local populations to labor market segmentation, exploiting ethnic differences to maintain division and competition among workers. The interactionist perspective, represented by Fredrik Barth, emphasizes the social construction of ethnic groups. Barth argues that ethnic identity is formed through processes of self-recognition and attribution, with ethnic boundaries maintained through social interactions and mobility. This approach shifts attention from intrinsic cultural characteristics to the dynamics of interaction that define ethnic boundaries. In summary, ethnicity is analyzed considering both cultural and socioeconomic aspects, showing how different theories intersect and contrast, offering a complex and articulated view of ethnic identities. The exploration of these theories provides a comprehensive understanding of the multifaceted nature of ethnicity in contemporary society, highlighting the ongoing relevance of these concepts in modern sociological and anthropological research.