Louis Comfort Tiffany (February 18, 1848 - January 17, 1933) was an American artist and designer who is best known for his work in stained glass and is the American artist most associated with the Art Nouveau movement. Tiffany was a painter and interior decorator and designed stained glass windows and lamps, glass mosaics, blown glass, ceramics, jewelry, enamels and metalwork.

Louis was the son of Charles Lewis Tiffany, founder of Tiffany and Company; and Harriet Olivia Avery Young. Louis married Mary Woodbridge Goddard (c1850-1884) on May 15, 1872 in Norwich, Connecticut and had the following children: Mary Woodbridge Tiffany (1873-1963) who married Graham Lusk; Charles Louis Tiffany I (1874-1874); Charles Louis Tiffany II (1878-1947); and Hilda Goddard Tiffany (1879-1908). After the death of his wife, he married Louise Wakeman Knox (1851-1904) on November 9, 1886. They had the following children: Louise Comfort Tiffany II (1887-1974); Julia DeForest (1887-1973);

He went to school at the Eagleswood Military Academy in Perth Amboy, New Jersey. His first artistic training was as a painter, studying under George Inness and Samuel Coleman in New York City, and Léon Bailly in Paris.

From about 1875 to 1878, when he became interested in glassmaking and worked several at glasshouses in Brooklyn. In 1879 he joined with Samuel Colman and Lockwood de Forest to form 'Louis Comfort Tiffany and Associated American Artists. Tiffany's leadership and talent, as well as by his father's money and connections, led this business to thrive.

The first Tiffany Glass Company was incorporated on December 1, 1885, which in 1900 became known as the Tiffany Studios.

Tiffany used opalescent glass in a variety of colors and textures to create a unique style of stained glass. This can be contrasted with the method of painting in glass paint or enamels on colorless glass that had been the dominant method of creating stained glass for several hundred years in Europe. Fellow artist and glassmaker John La Farge was Tiffany's chief competitor in this new American style of stained glass. Both La Farge and Tiffany had learned their craft at the same glasshouses in Brooklyn in the late 1870’s.

In 1893 Tiffany built a new factory, called the Tiffany Glass Furnaces, which was located in Corona, Queens, New York. In 1893 his company also introduced the term, Favrile in conjunction with his first production of blown glass at his new glass factory. Some early examples of his lamps were exhibited in the 1893 World's Fair in Chicago.

He trademarked Favrile (from the old French word for handmade) on November 13, 1894. He later used this word to apply to all of his glass, enamel and pottery. Tiffany's first commercially produced lamps date from around 1895. Much of his company's production was in making stained glass windows and Tiffany lamps, but his company designed a complete range of interior decorations. At its peak, his factory employed more than 300 artisans.

He used all his skills in the design of his own house, the 84-room Laurelton Hall, in Oyster Bay, Long Island, completed in 1906. Later this estate was donated to his foundation for art students along with 60 acres (243,000 m²) of land, but destroyed by a fire in 1949 after it had been sold.

Tiffany maintained close ties with the family firm. The Tiffany Company sold many products produced by the studios. He became Artistic Director of Tiffany & Co. after his father's death in 1902. The Tiffany Studios remained in business until 1932.

He died on January 17, 1933, and was buried in Greenwood Cemetery in Brooklyn, New York.