The aim of this article is to discuss why the principle of equality and non-discrimination, although foundational to international human rights law, remains an unfulfilled promise in the context of immigration. Nationality is now widely considered as a suspect ground of discrimination, yet contemporary immigration and citizenship laws increasingly use meritocratic criteria to distinguish among migrants. Although framed in universal terms, these criteria create differences of treatment among migrants based on their income, level of education and economic worth. However, from a legal perspective such differences of treatment rarely amount to prohibited discrimination. Looking at the case law of the European Court of Human Rights, this article argues that the normative content of the equality and non-discrimination principle fails to challenge such differences of treatment. Moreover, the proportionality test is used as a judicial restraint mechanism which prevents the effective enforcement of the equality requirement by international and domestic courts in the context of immigration.