The Isleworth Mona Lisa is an early 16th-century oil on canvas painting depicting the same subject as Leonardo da Vinci's Mona Lisa, though with the subject depicted as being a younger age. The painting is thought to have been brought from Italy to England in the 1780s, and came into public view in 1913 when the English connoisseur Hugh Blaker acquired it from a manor house in Somerset, where it was thought to have been hanging for over a century. The painting would eventually adopt its unofficial name of Isleworth Mona Lisa from Blaker's studio being in Isleworth, West London. Since the 1910s, experts in various fields, as well as the collectors who have acquired ownership of the painting, have asserted that the major elements of the painting are the work of Leonardo himself, as an earlier version of the Mona Lisa.

The Mona Lisa is a half-length portrait painting by Italian artist Leonardo da Vinci. Considered an archetypal masterpiece of the Italian Renaissance, it has been described as "the best known, the most visited, the most written about, the most sung about, [and] the most parodied work of art in the world". The painting's novel qualities include the subject's enigmatic expression, monumentality of the composition, the subtle modelling of forms, and the atmospheric illusionism.