Reunification Day (Vietnamese: Ngày Thống nhất), Victory Day (Ngày Chiến thắng), Liberation Day (Ngày Giải phóng or Ngày Giải phóng miền Nam), or the official name Day of Southern Liberation for National Reunification (Giải phóng miền Nam, thống nhất đất nước)^[​2] is a public holiday in Vietnam that marks the event when North Vietnamese and Việt Cộng forces captured Saigon (now Ho Chi Minh City) on April 30, 1975. This signalled the end of the Vietnam War, known in Vietnamese as Kháng chiến chống Mỹ cứu nước ("Anti-American Resistance War for National Salvation") or Chiến tranh Việt Nam ("Vietnam War"). It was the start of the transition period toward reunification, which occurred in the national election^{[citation needed]} for national reunification on July 2, 1976, when the Republic of South Vietnam and North Vietnam merged the two independent countries, forming the modern-day Vietnam.^[​3]

In the Overseas Vietnamese community, the day is remembered as the "Fall of Saigon", "Black April" (Tháng Tư Đen),^[​4][​5] "National Day of Shame" (Ngày Quốc Nhục) or "National Day of Hate" (Ngày Quốc Hận).^[​4][​6] This is a commemorative day for exiled Vietnamese who served, were affected, and displaced in those overseas communities, and as such is a day of reflection. Many Americans of multiple ethnicities observe the day for remembrance and solidarity.