Richard Branson dropped out at 15.
The Virgin Group founder is an international powerhouse currently worth about $4.9 billion, according to Forbes.
Branson founded his first business, Student magazine, after dropping out of high school at 15 and has spoken out against the university system on his blog.
Nearly 50 years after dropping out, he has overseen approximately 500 companies, with his brand currently on somewhere between 200 and 300 of them.
David Karp dropped out at 15.
At the age of 15, Karp dropped out of an elite Bronx High School of Science and developed Tumblr, the blog-hosting and social network company, in 2007 in the "back bedroom of his mother's modest Manhattan apartment."
He sold the blog-hosting company to Yahoo for $1.1 billion in 2013, when his net worth reportedly exceeded $200 million, and he remains as the company's CEO.
Aretha Franklin dropped out at 15.
Regarded as a child prodigy, Franklin recorded her first tracks at age 14 and performed with her father's traveling Gospel revival show, according to Bio. She dropped out of high school at 15 to care for her first child.
Franklin has since received numerous honorary degrees from universities like Harvard, Princeton, Yale, and the Berklee College of Music.
In 1987, Franklin became the first female artist to be inducted into the Rock and Roll Hall of Fame. She has sung at the inauguration of three US presidents, including Bill Clinton and Barack Obama.
Franklin has 18 Grammys under her belt, and in 1994 was honored with a Grammy Lifetime Achievement Award.
Joe Lewis dropped out at 15.
Lewis dropped out of high school at 15 to run his father's catering business, Tavistock Banqueting, and is currently worth about $5.3 billion, according to Forbes.
The businessman — who works from his yacht most of the year — owns a planned community in Lake Nona, near Orlando, which is now one of the fastest-growing developments in America and houses a medical city that includes the University of Central Florida College of Medicine and Health Sciences Campus, Sanford-Burnham Medical Research Institute, the Orlando VA Medical Center, and a University of Florida Research and Academic Center.
As the main investor in Tavistock Group, Lewis owns more than 200 companies, according to Forbes, including London Premiership soccer team Tottenham Hotspur (Spurs), a stake in UK's largest pub operator, Mitchell's & Butlers plc, and approximately 135 restaurants and various resorts throughout the world.
He also has a covetable art collection that includes works by Picasso, Matisse, Lucian Freud, and Francis Bacon.
Mike Hudack dropped out at 16.
Hudack dropped out of high school and started working at a small internet security and privacy company in Connecticut at 16. He then moved to New York and worked as a consultant for Time Warner.
In 2005, he founded Blip.tv, a hosting platform for creators of digital video content. In 2012, he left his position as CEO to become Facebook's product manager.
Philip Emeagwali dropped out at 13.
Called an "unsung hero of the internet," the supercomputer scientist dropped out of high-school in Nigeria due to war conditions and lack of tuition money. According to Time, he was considered a math prodigy and continued to study on his own, earning an equivalency diploma and later a scholarship to Oregon College of Education in the US.
In 1987, Emeagwali came up with the formula for allowing a large number of computers to communicate at once. The record-breaking experiment was a practical and inexpensive way to use machines to speak to each other all over the world.
The discovery earned him the IEEE Gordon Bell Prize in 1989, and he has since been hailed as one of the fathers of the Internet, according to Time.
Quentin Tarantino dropped out at 15.
The Oscar winner attended Narbonne High School in Harbor City, California, until he dropped out at the age of 15 and started working as an usher at an adult film theater while taking acting classes, according to Bio.
While working at the Video Archives in his early 20s, Tarantino wrote the scripts for "True Romance" and "Natural Born Killers," but it was his directorial debut in "Reservoir Dogs" in 1992 that won him wide critical acclaim.
He's been nominated for several Academy Awards and is the winner of two — for "Django Unchained" and "Pulp Fiction."
Francois Pinault dropped out at 11.
According to Forbes, the French businessman dropped out of his private high school in 1947 to work at his father's lumber mill in part because his school mates made fun of his poor background.
Today, as the majority shareholder of fashion conglomerate PPR, the billionaire businessman owns high-end fashion houses including Gucci, Stella McCartney, Alexander McQueen, and Yves Saint Laurent.
He also owns Christie's Auction House and is currently worth around $12.9 billion, according to Forbes.
David H. Murdock dropped out at 14.
The self-made billionaire businessman dropped out of high school in the ninth grade and worked at a gas station before being drafted into the Army in 1943, according to Forbes.
After World War II, Murdock bought his first business, a Detroit diner, and sold it several months later for a $700 profit. Now, after a lifetime of buying, building and selling, he's worth an estimated $2.9 billion, according to Forbes.
The Dole Foods CEO took the company private in 2013 in a deal that valued the company at $1.6 billion.
At 92, Murdock is somewhat of a health nut — he told the New York Times he swore off red meat long ago and eats as many as 20 fruits and vegetables a day, going so far as to pulverize banana peels and orange rinds into the smoothies he drinks two to three times a day — and he says he wants to live forever.
George Foreman dropped out at 15.
Foreman dropped out of school in the ninth grade and ran with street gangs until he joined the Job Corps in 1965, where he first started training as a boxer, according to Bio.
He has been inducted into the World Boxing Hall of Fame and the International Boxing Hall of Fame as a two-time World Heavyweight Champion and Olympic gold medalist.
Most of Foreman's fortune came after his boxing career as a spokesperson for Russell Hobbs Inc.'s fat-reducing grill called the George Foreman Grill, which has earned him an estimated net worth of $250 million, according to TheRichest.
James H. Clark dropped out at 16.
The self-made billionaire American businessman and cofounder of Netscape dropped out of high school at 16 after getting into some trouble and joined the US Navy, where he earned his high school equivalency degree, began learning about electronics, and made money on the side by loan-sharking cash to other recruits at interest rates of 40%, according to Forbes.
Considered the first Internet billionaire, Clark's timely investments in companies like Apple, Facebook, and Twitter have earned him an estimated current worth of about 1.85 billion, according to Forbes.
His philanthropic efforts include financially backing the Japanese dolphin hunting documentary, "The Cove" and pledging $60 million toward science research in 2013.