Irving Grant Thalberg (May 30, 1899–September 14, 1936) was an American film producer during the early years of motion pictures. He was called "The Boy Wonder" for his youth and his extraordinary ability for selecting the right scripts, choose the right actors, gather the best production staff, and making very profitable films out of them.

Thalberg was born in New York City of German immigrant parents. He had a bad heart and was plagued with other ailments all of his life. Upon completing high school, he was employed by Universal Pictures' New York office, where he worked as personal secretary to legendary studio founder Carl Laemmle, the boss of Universal Studios. Irving Thalberg was bright and persistent, and by age 21 was executive in charge of production at Universal City, the studio's California production site. He quickly established his tenacity as he battled with Erich von Stroheim over the length of Foolish Wives (1922), and controlled every aspect of the production of The Hunchback of Notre Dame (1923). In 1924, he left Universal for Louis B. Mayer Productions, which shortly thereafter linked up with Metro Pictures to become Metro Goldwyn Mayer.

The Big Parade (1925), directed by King Vidor, was Thalberg's first major triumph at MGM. Until 1932, when he suffered a major heart attack, he supervised every important studio production, and combined careful preproduction groundwork with prerelease sneak previews which measured audience response.

Since 1927 he was married to the beautiful actress Norma Shearer, whose career flourished as the wife of the most powerful and respected producer in Hollywood. They had two children, Irving Jr. and Katherine.

Upon his illness, Louis B. Mayer, who had come to resent Thalberg's power and success, replaced him with David O. Selznick and Walter Wanger. When he returned to work in 1933, it was as one of the studio's unit producers. Nonetheless, he helped develop some of MGM's most prestigious ventures, including Grand Hotel (1932), Mutiny on the Bounty (1935), China Seas (1935), A Night at the Opera (1935), with the Marx Brothers, San Francisco (1936), and Romeo and Juliet (1936). Thalberg died of pneumonia at age 37, during the preproduction of A Day at the Races (1937), with the Marx Brothers, and Marie Antoniette (1938), with his wife.

The Irving G. Thalberg Memorial Award, presented by the Academy of Motion Picture Arts and Sciences, is named for him.