It took Leonardo da Vinci a total of 12 years to paint the lips of the Mona Lisa. But there is much debate about the length of time that it actually took.

According to reputable sources, it took Leonardo da Vinci 12 years to complete the lips. Other sources say that it took as little as three years, while others say it took a painstaking 22 years. Experts at the Louvre Museum in Paris, France have verified that it only took da Vinci 12 years. It took so long because da Vinci wanted to capture an air of mystery in her smile.