The National Social Democratic Front (Vietnamese: Mặt trận Quốc gia Dân chủ Xã hội), later named the Social Democratic Alliance (Vietnamese: Liên minh Dân chủ Xã hội), was a South Vietnamese political party which was effectively a federation of different groups, united by their anti-communist stance.

The Democratic Party, purportedly representing farmers, workers and small traders, participated in the presidential election of 1967, supporting President Nguyễn Văn Thiệu and his military rule.

The parties' federation was functional during Nguyễn Văn Thiệu's tenure as president and changed its name to Social Democratic Alliance in 1973.

The Paris Peace Accords of 1973 was a turning point in the war, causing the end of American intervention in Vietnam.

Many members of the Front and South Vietnamese government were executed by the new administration, but others fled from Vietnam.