National Social Welfare Day, also known as National Social Work Day or Thai Volunteers Day, is observed in Thailand every October 21. This day commemorates the birthday of Princess Mother Srinagarindra, who was instrumental in establishing numerous social welfare projects throughout the country. Born on October 21, 1900, she dedicated her life to helping the underprivileged, particularly in remote areas populated by hill tribes. After becoming a widow in 1929, she utilized her resources to fund initiatives such as the New Life Foundation and various educational and public health projects. The day serves to highlight her contributions, including the establishment of schools, medical volunteer units, and scholarships for students. In 1985, the Thai government officially designated her birthday as National Social Welfare Day to honor her legacy in social welfare.