Voluntary organizations are non-profit groups that work to help disadvantaged sections of society. They operate voluntarily and without state control. The document discusses how voluntary organizations in India work to supplement government development efforts, especially in rural areas. They aim to empower local communities and make them self-sufficient through activities like spreading information, demonstrating use of local resources, and mobilizing community financing. The Seventh Five-Year Plan in particular recognized the role of voluntary organizations in development work alongside welfare activities.