Thomas J. Tull (born June 9, 1970) is an American billionaire businessman, entrepreneur, and film producer. He is co-chairman of TWG Global, a holding group where he is developing investments using artificial intelligence and other technologies to guide investing. He is the former chairman and chief executive officer (CEO) of Legendary Entertainment and Tulco LLC.

Tull grew up in Endwell, New York, the son of a dental hygienist single mother. As a youth, Tull was an athlete, playing baseball and football. Tull graduated from Hamilton College in 1992.

After college, Tull abandoned plans to become a lawyer and instead went into business, starting a chain of laundromats. Among his innovations were different prices according to demand at different times of day. Tull next went into the field of financing, buying and selling several tax and accounting offices. He later became chief of operations of Tax Services of America. His business was buying units from franchisees of Jackson Hewitt Tax Services rolling up and consolidating operations. This group of former independent franchisees was eventually sold back to Jackson Hewitt. People who had established franchised locations often preferred being salaried managers. In 2001, Tull left Interactive Technology Funds to join the Convex Group, an Atlanta-based investment group. His firm invested in entertainment, where Tull began to learn the entertainment business. After discussing the potential of private equity with a film executive in 2003, Tull quit Convex, raising $600 million in equity to finance the production of movies under the Legendary Pictures banner.

Tull founded Legendary Entertainment in 2005, becoming the CEO and chairman. The company entered into a partnership with Warner Bros. that same year to jointly finance and produce films. In 2009, Tull became the majority shareholder of Legendary, in a buyout of the original investors. The Warner deal was followed by a similar deal with Universal Studios in 2013. He also helped produce the film Blackhat. Legendary was one of the first film production companies to use technology and data analytics to improve the way movies are marketed. Shortly after starting Legendary, Tull built a new analytics division within the company, which uses data to improve marketing decisions, in addition to other key decisions.

In January 2016, Legendary was acquired by the Wanda Cultural Industry Group for $3.5 billion, with Tull retaining a 20% stake. One year later, in January 2017, Tull left the company.

Tull describes himself as a "fanboy" of comics, and several of the films produced by Legendary were personal favorites of Tull, including Watchmen, 300, and The Dark Knight. Watchmen had been in "development hell" for years when Tull arranged to pick up the rights. 300 had been turned down by other studios. Tull also describes himself as a "gamer", and co-founded the short-lived Brash Entertainment to work on film-to-video game conversions. Other major films include Inception, The Hangover and its sequels, Man of Steel, and others.

In 2017, Tull founded Tulco, LLC, a Pittsburgh-based privately held holding company. Tulco invests in companies in large industries and helps its portfolio companies apply technology such as artificial intelligence, machine learning and predictive data analytics. Among Tulco’s investments is Acrisure, an insurance broker that acquired Tulco’s AI insurance business in July 2020 for $400 million.

In 2022, Tull started fundraising as the new head of the United States Innovative Technology (USIT) Fund, focusing on start-up companies and industries including AI, quantum computing and cybersecurity, space technology including satellites, and biotech. The fund's investments have included Anduril Industries, which was founded by Palmer Luckey, and Capella Space, which are two companies building satellites with the capability to take images at night and through cloud cover.