Veinticinco de Mayo (Spanish: 25 May) is the May 25 day. It's Argentina's National Day, and may refer to:
- The day during the May Revolution when the Primera Junta (first autonomous government in Argentina) was instituted
- Geographic locations in Argentina
- Veinticinco de Mayo Partido, partido in Buenos Aires Province, Argentina
- Veinticinco de Mayo, Buenos Aires, city in Buenos Aires Province, Argentina
- Veinticinco de Mayo Department, Chaco, Chaco Province, Argentina
- Veinticinco de Mayo Department, Misiones, Misiones Province, Argentina
- Veinticinco de Mayo Department, Río Negro, Río Negro Province, Argentina
- Veinticinco de Mayo, La Pampa, La Pampa Province, Argentina
- Veinticinco de Mayo, Uruguay, Florida Department, Uruguay
- Ships
- ARA Veinticinco de Mayo (cruiser), a cruiser (C-2) which served Argentina during World War II
- ARA Veinticinco de Mayo (V-2), an aircraft carrier which served Argentina up to 1990