The concept of "citizen" differs across disciplines. Drawing on insights from multiple disciplines, this paper argues that being respected is the fundamental ethical basis for citizens and proposes a normative framework. In this framework, people being respected as citizens relies on three foundations: autonomy, boundary, and equality. Autonomy means a citizen has the right to make choices and act independently and freely. Nevertheless, this freedom is not boundless. Boundary consciousness is the manifestation of a citizen. Being a citizen implies the presence of boundaries that safeguard individual freedom and autonomy while prohibiting violations of others' boundaries. Equality is the fundamental element of being a citizen. Subjects in disadvantaged unequal relationships find difficulty in becoming real citizens. People engage in behaviors that harm themselves and others due to differences in social cognition, embedded social relationships that blur behavioral boundaries, and hierarchical cultures that cause status inequality. This theoretical framework can provide ethical and normative guidance for citizen cultivation. Citizen cultivation should focus on fostering people's autonomy of being responsible and accountable, recognizing and respecting self and others' necessary boundaries, and constructing individuals' subjective equality consciousness.