The Derby Day is a large oil painting showing a panoramic view of the Epsom Derby, painted by William Powell Frith over 15 months from 1856 to 1858. It has been described by Christie's as Frith's "undisputed masterpiece" and also "arguably the definitive example of Victorian modern-life genre". The original version is in Tate Britain in London. As with many of Frith's works, he painted a second version many years later, which is now in the Manchester Art Gallery. A much smaller but well-finished oil study was sold in 2011.