There are two major Derbies commonly referred to as "Derby Day":

• The Kentucky Derby in the United States is held annually on the first Saturday in May. In 2025, the Kentucky Derby will take place on Saturday, May 3, 2025

• The Epsom Derby (also known as the Derby Stakes) in England is held annually on the first Saturday in June. In 2025, the Epsom Derby will be held on Saturday, June 7, 2025

So, depending on which Derby you mean:

• Kentucky Derby Day 2025: May 3, Saturday
• Epsom Derby Day 2025: June 7, Saturday