The purpose of this paper is to outline a general theoretical framework regarding the cultural, linguistic and phenotypical symbols that can mark ethnic boundaries. Reflection on ethnic symbols will be guided by an anti-essentialist, relational and dynamic approach to ethnicity, as well as the idea that, beyond its various local embodiments, ethnicity presents a unitary core that transcends the distinction between the pre-modern and modern worlds. In the paper, the relationship between the symbols used to signal or determine ethnic membership and the myths of origin translated into the principle of recruitment by birth will be investigated. The distinctions between symbols of auto- and hetero-identity and between criteria and indicia of identity will also be discussed. We will then explore some aspects of the selection, organisation, mobilisation and evolution of the sets of symbols. The focus will subsequently be placed on the symbolic dimension of the interactions between the malleable aspects of ethnicity and the constraints that limit the freedom of social actors. Finally, we will look at the complex contextual variations in sets of auto-identity symbols.