Founder's Day, Founders Day, or Founders' Day and variations may refer to:
Founder's Day (Rome), better known as the Parilia, a festival in ancient Rome eventually taken to honor the city's founding Founders' Day (Ghana), a public holiday in Ghana Founder's Day (Music Festival) an annual campus festival at Vassar College Founders' Day (Scouting), a Scouting commemoration associated with Scouts' Day Founders Day (South Africa), an observance and former public holiday in South Africa "Founder's Day" (The Vampire Diaries), a 2010 episode of the TV series The Vampire Diaries Founders Day, a 2023 American slasher film directed by Erik Bloomquist. Founders' Day, a former public holiday in Rhodesia Founder's Day, a holiday of the American Revolution Founder's Day, an annual event at many Indian private boarding schools, such as The Doon School