King Harold Day is an annual observance occurring on October 14th, commemorating the demise of King Harold II, the final Anglo-Saxon king of England, during the Battle of Senlac Hill in 1066. Held on a Saturday near the anniversary of the Battle of Hastings, the festival takes place in Waltham Abbey, where Harold served as the local Lord of the Manor before ascending to the throne.

Organized by the King Harold Day Society, the event centers around the monument, featuring a narrative that unfolds from King Harold's death to the journey of his daughter, Princess Gytha, who fled the country following her father's demise.