Vacheron Constantin SA (French pronunciation: [vaʃəʁɔ̃ kɔ̃stɑ̃tɛ̃]) is a Swiss luxury watch and clock manufacturer founded in 1755. Since 1996, it has been a subsidiary of the Swiss Richemont Group. Vacheron Constantin is one of the oldest watch manufacturers in the world with an uninterrupted watchmaking history since its founding. It employs around 1,200 people worldwide as of 2018, most of whom are based in the company's manufacturing plants in Canton of Geneva and Vallée de Joux in Switzerland.
Vacheron Constantin is a highly regarded watch manufacturer. Over the years, notable Vacheron Constantin patrons and timepieces owners include Queen Elizabeth II, Alexander I of Yugoslavia, Pope Pius XI, Napoléon Bonaparte, Marlon Brando, William James, John D. Rockefeller, Diana Princess of Wales, Harry S. Truman, and the Wright brothers. The Vacheron Constantin pocket watch No. 402833 (1929), which was owned by King Fuad I of Egypt, ranks as one of the most expensive watches ever sold at auction, fetching US$2.77 million (3,306,250 CHF) in Geneva on April 3, 2005. In 2015, Vacheron Constantin introduced the pocket watch Reference 57260, which currently holds the title of the most complicated mechanical watch ever made, with 57 horological complications.