Mona Lisa (also known as La Gioconda or La Joconde) is a 16th-century portrait painted in oil on a poplar panel by Leonardo di ser Piero da Vinci during the Renaissance in Florence, Italy. The work is currently owned by the Government of France and is on display at the Musée du Louvre in Paris under the title Portrait of Lisa Gherardini, wife of Francesco del Giocondo.

Mona Lisa is named for Lisa del Giocondo, a member of the Gherardini family of Florence and Tuscany painting and the wife of wealthy Florentine silk merchant Francesco del Giocondo. The Mona Lisa painting was commissioned for their new home and to celebrate the birth of their second son, Andrea. The sitter's identity was ascertained at the University of Heidelberg in 2005 by a library expert who discovered a 1503 margin note written by Agostino Vespucci. Scholars have been of many minds, identifying at least four different paintings as the Mona Lisa and several people as its subject. Leonardo's mother Caterina Buti del Vacca in a distant memory, Isabella of Naples or Aragon, Cecilia Gallerani, Costanza d'Avalos, Duchess of Francavilla‎ who was also called the "merry one" or La Gioconda, Isabella d'Este, Pacifica Brandano or Brandino, Isabela Gualanda, Caterina Sforza, and Leonardo himself have all been named the sitter. Today the subject's identity is held to be Lisa, which has always been the traditional view.The painting is a half-length portrait and depicts a seated woman (it is almost unanimous that she is Lisa del Giocondo) whose facial expression is frequently described as enigmatic. The ambiguity of the subject's expression, the monumentality of the composition, and the subtle modeling of forms and atmospheric illusionism were novel qualities that have contributed to the continuing fascination and study of the work. The image is so widely recognized, caricatured, and sought out by visitors to the Louvre that it is considered the most famous painting in the world.

This figure of a woman, dressed in the Florentine fashion of her day and seated in a visionary, mountainous landscape, is a remarkable instance of Leonardo's sfumato technique of soft, heavily shaded modeling. The Mona Lisa's enigmatic expression, which seems both alluring and aloof, has given the portrait universal fame. Reams have been written about this small masterpiece by Leonardo, and the gentle woman who is its subject has been adapted in turn as an aesthetic, philosophical and advertising symbol, entering eventually into the irreverent parodies of the Dada and Surrealist artists. The history of the panel has been much discussed, although it remains in part uncertain. According to Vasari, the subject is a young Florentine woman, Monna (or Mona) Lisa, who in 1495 married the well-known figure, Francesco del Giocondo, and thus came to be known as ``La Gioconda''. The work should probably be dated during Leonardo's second Florentine period, that is between 1503 and 1505. Leonardo himself loved the portrait, so much so that he always carried it with him until eventually in France it was sold to François I, either by Leonardo or by Melzi.

From the beginning it was greatly admired and much copied, and it came to be considered the prototype of the Renaissance portrait. It became even more famous in 1911, when it was stolen from the Salon Carré in the Louvre, being rediscovered in a hotel in Florence two years later. It is difficult to discuss such a work briefly because of the complex stylistic motifs which are part of it. In the essay ``On the perfect beauty of a woman'', by the 16th-century writer Firenzuola, we learn that the slight opening of the lips at the corners of the mouth was considered in that period a sign of elegance. Thus Mona Lisa has that slight smile which enters into the gentle, delicate atmosphere pervading the whole painting. To achieve this effect, Leonardo uses the sfumato technique, a gradual dissolving of the forms themselves, continuous interaction between light and shade and an uncertain sense of the time of day.

Art historians are probing a real life Da Vinci Code style mystery after discovering tiny numbers and letters painted into the eyes of the artist's enigmatic Mona Lisa painting. Leonardo Da Vinci 500-year-old Renaissance masterpiece has long been steeped in mystery, and even today the true identity of the woman with the alluring smile still far from certain. The painting also featured in the Dan Brown blockbuster The Da Vinci Code, which was turned into a 2006 film starring Tom Hanks. His character interprets secret messages hidden in the Mona Lisa and Da Vinci's other works, including The Last Supper. Some historians believe that Da Vinci was homosexual and that his love of riddles led him to paint himself as a woman. Another theory is that the Mona Lisa is Lisa Gheradini, the wife of Florence merchant - or possibly even the artist's mother.

The Leonardo Da Vinci painting title stems from a description by Giorgio Vasari in his biography of Leonardo published in 1550, 31 years after the artist's death. "Leonardo undertook to paint, for Francesco del Giocondo, the portrait of Da Vinci Mona Lisa, his wife...." (one version in Italian: Prese Lionardo a fare per Francesco del Giocondo il ritratto di mona Lisa sua moglie).[26] In Italian, ma donna means my lady. This became madonna, and its contraction mona. Mona is thus a polite form of address, similar to Ma’am, Madam, or my lady in English. In modern Italian, the short form of madonna is usually spelled Monna, so the title is sometimes Monna Lisa, rarely in English and more commonly in Romance languages such as French and Italian.

At his death in 1525, Leonardo's assistant Salai owned the portrait named in his personal papers la Gioconda which had been bequeathed to him by the artist. Italian for jocund, happy or jovial, Gioconda was a nickname for the sitter, a pun on the feminine form of her married name Giocondo and her disposition. In French, the title La Joconde has the same double meaning.