This study examines the value of social solidarity in the Dīgha Nikāya and explores its implications for contemporary Buddhist social welfare. Based on the concept of dependent origination (paṭiccasamuppāda), social solidarity is analyzed through two categories: interdependence and moral responsibility. The findings show that the Dīgha Nikāya presents social solidarity not only as individual ethical practice but also as social practice directed toward others and the community. These values are closely related to human dignity, mutual care, and social integration, providing a foundation for relationship-centered Buddhist social welfare practice.