The Arbaeen Pilgrimage, as the world's largest annual peaceful gathering with over 21 million pilgrims in 1404 SH (2025 CE), offers a practical and dynamic model of Islamic popular governance that extends from spontaneous mawakib (service stations) to the broad civilizational capacities of the Islamic Ummah. This study aims to explain the Arbaeen Pilgrimage as a model of popular self-organization and the manifestation of popular wilayah (guardianship/authority) in contemporary Islamic governance. The research employs a qualitative descriptive-analytical approach with a case study design, drawing on library resources, official documents from the holy shrines, field reports from mawakib, and participatory observations along the Najaf–Karbala route. The theoretical framework is built upon theories of network governance, social capital, and the jurisprudential-political foundations of Imam Hussein's conduct and wilayah teachings. Findings reveal that the Arbaeen Pilgrimage exhibits five key characteristics: 1) a decentralized network structure and self-organizing mawakib; 2) voluntary service delivery based on sincerity, charity, and sacrifice without reliance on state budgets; 3) maximum production of social capital through interpersonal trust, trans-ethnic and trans-sectarian unity, and synergy among diverse social strata; 4) outstanding logistical efficiency in delivering large-scale services (food, accommodation, healthcare, security) beyond the capacity of centralized bureaucratic systems; and 5) popular wilayah and service-oriented leadership as the foundation of Islamic governance, where leadership rests on service and heartfelt connection to the divine authority rather than centralized power. Unlike Western state-centered or liberal market-driven models, this paradigm is rooted in popular wilayah, self-organization, and Husseini service, functioning as a