Witness protection is indispensable to the effective administration of justice because witnesses who face intimidation, retaliation, or violence are less likely to cooperate with law enforcement and judicial institutions. Despite growing scholarship on witness protection, comparative studies rarely examine how constitutional foundations, legal frameworks, and administrative enforcement mechanisms interact across jurisdictions with different levels of institutional development. This article aims to analyse the constitutional, legal, and procedural dimensions of witness protection in Nigeria, India, and the United States in order to identify major weaknesses, institutional contrasts, and reform lessons. Using doctrinal legal research combined with a comparative approach, the study examines constitutions, statutes, policy instruments, judicial decisions, and relevant scholarly literature from the three jurisdictions. The study finds that the United States has the most institutionalised and effective witness protection regime, supported by a clear statutory basis, administrative coordination, and sustained state capacity. India has made important progress by constitutionalising witness protection through judicial intervention and by adopting the Witness Protection Scheme, but its implementation remains uneven due to procedural delays, inter-state disparities, and limited resources. Nigeria, by contrast, continues to face the most serious structural deficiencies, including weak institutional coordination, restricted legal coverage, political interference, corruption, and inadequate funding. The novelty of this article lies in its integrated comparison of constitutional recognition, legal design, and practical enforcement across three contrasting systems, showing that effective witness protection depends not only on legal rules but also on institutional autonomy and administrative capacity. The article argues that reform in Nigeria and further consolidation in India must be grounded in each country’s socio-political and legal context.