Religious pluralism in Muslim-majority societies raises a persistent question concerning how Islamic ethical and legal reasoning can contribute to public life without undermining equal citizenship, religious freedom, and social cohesion. This study aims to reconstruct Islamic public reason as a normative and institutional framework for plural citizenship by examining how religious identity, legal authority, minority recognition, and state coercion are formulated across different constitutional settings. It employs qualitative comparative document analysis, directed content analysis, and comparative normative interpretation of constitutional texts, judicial decisions, international human-rights instruments, and Islamic declarations relating to Indonesia, Morocco, and Tunisia. The findings demonstrate, first, that these states exhibit constitutional hybridity rather than a simple Islamic–secular divide, combining religious commitments with equality, freedom, national sovereignty, and cultural plurality. Second, Islamic normativity cannot be equated with state-enforceable law, because theological truth, moral obligation, juristic judgment, and coercive legislation represent distinct forms of authority. Third, plural citizenship requires more than formal nationality or passive toleration; it depends on equal administrative recognition and effective opportunities to challenge public classifications and decisions. Fourth, social cohesion is more sustainably generated through accountable disagreement than through enforced religious uniformity. On this basis, the study proposes an Islamic Public Reason Framework for Plural Citizenship comprising normative openness, reciprocal civic justification, differentiated legal authority, and institutional contestability. The framework advances Islamic and Islamicate scholarship by preserving the public relevance of Islamic ethical reasoning while requiring every exercise of coercive authority to remain proportionate, reviewable, and accountable to citizens as political equals.