Bloody Friday may refer to:
- Bloody Friday (1919), also known as the Battle of George Square, a riot in Glasgow in 1919
- Bloody Friday (Minneapolis), a police shooting of pickets in Minneapolis in 1934
- Bloody Friday (1968), demonstrations against the Brazilian military regime and civil responses to police repression
- Bloody Friday (1970), an attack by construction workers on students protesting the Vietnam War
- Bloody Friday (1972), a series of bombings by the Provisional Irish Republican Army
- Bloody Friday (1993), an ethnic cleansing against the Kongo during the Angolan Civil War
- Bloody Friday (1998), a confrontation between university students and police forces during the May 1998 riots in Indonesia
- Bloody Friday (2008), the stock market crash on 24 October 2008, which saw many of the world's stock exchanges experience the worst declines in their history, with drops of around 10% in most indices
- Bloody Friday (2015), a series of terrorist attacks, involving mainly the Islamic State of Iraq and the Levant, occurred on June 26
- Bloody Friday (film), a 1972 German-Italian crime film
- Bloody Friday (2022), a massacre of protesters by regime forces in Zahedan, Iran