Mark Zuckerberg, Steve Jobs, and 21 other tech moguls who never graduated college

Zuckerberg never did complete either of his two majors (psychology and computer science). He launched "thefacebook.com" while a student at Harvard University, but he dropped out during his sophomore year to move to Palo Alto and work on his company full-time.

Mullenweg developed the open-source software for blogging platform WordPress as a 19-year-old freshman at the University of Houston, where he was studying philosophy and political science. By the start of his junior year, he left college for a job at CNET in San Francisco.

Like many successful tech moguls, Park dropped out of Harvard. In 1998, he abandoned his major in computer science to pursue a career as an entrepreneur. After a brief stint as a Morgan Stanley analyst, he started Fitbit in 2007.

The Collison brothers grew up in Ireland and both came to Boston for college: Patrick Collison at MIT, John Collison at Harvard. They hatched the idea for their first business — an online auction management company named Auctomatic — at a local pub, and dropped out of college to build the company's technology in San Francisco.

They sold Auctomatic in 2008 for $5 million, and became teenage millionaires.

Dorsey is a two-time college dropout. He first enrolled at the University of Missouri-Rolla, but he transferred to NYU after two years. He reportedly thought of the idea for Twitter while at NYU, where he dropped out a semester short of graduating and moved to the West Coast to work with a tech company.

Ek grew up in Sweden, and enrolled in college in 2002 at the country's KTH Royal Institute of Technology to study engineering. He lasted only eight weeks, when he found out his entire first year would be devoted to theoretical mathematics. He soon started taking gigs at various tech companies.

As a kid growing up in Chicago, Ellison planned to attend medical school at USC, get married and have kids, and move to Los Angeles working as a doctor. However, that never happened. He tried getting an undergraduate degree twice — once at the University of Illinois at Urbana-Champaign (for two years), and again at the University of Chicago (where he lasted only one semester).

After dropping out a second time, Ellison moved to California amid the burgeoning tech scene.

As a senior in high school, Parker was making $80,000 a year through various programming and coding projects. It was enough money for Parker to convince his parents that he didn't have to go to college, and he instead joined up with Shawn Fanning to launch music-sharing website Napster in 1999.

Williams grew up in a small town in Nebraska, and enrolled for college at the nearby University of Nebraska-Lincoln. However, he felt college was a "waste of time," and lasted only a year-and-a-half taking as few classes as possible and without ever declaring a major. He then moved to Florida and bounced around various cities doing freelance work and tech jobs.

Jobs attended Reed College in Portland, Oregon, a private university he once said in a commencement speech was "almost as expensive as Stanford." He reportedly dropped out after one semester, but he stayed in the area and attended classes that interested him. One of those classes was calligraphy, taught by a Trappist monk named Robert Palladino, who Jobs later credited with teaching him about typefaces that he later added to the Mac personal computer he developed.

Koum enrolled in San Jose State University while also working as a security tester at Ernst & Young. While on assignment for EY, Koum was brought on to help out at Yahoo, where he met an employee who went on to be his future WhatsApp cofounder, Brian Acton.

Koum switched jobs to become an infrastructure engineer at Yahoo, and was soon inundated with doing work on Yahoo's servers. Koum said he "hated school anyway," and dropped out to devote his time to Yahoo.

Moskovitz studied computer science at Harvard, where he was roommates with Mark Zuckerberg. Moskovitz reportedly volunteered to help Zuckerberg work on his new website, and learned a coding language in "a couple of days" to be able to work. Along with Zuckerberg, Moskovitz dropped out of Harvard to move to Palo Alto and work on Facebook full-time.

Kalanick, a California native, enrolled in UCLA to study computer engineering. Through the school's Computer Science Undergraduate Association, he met two classmates named Michael Todd and Vince Busam. Kalanick worked with four other students out of Busam's dorm room to develop a peer-to-peer search engine called Scour.

Kalanick dropped out of school in 1998 to work for Scour full-time, and survived by collecting unemployment as the company looked to secure funding.

Ferdowsi attended MIT and studied computer science. In the summer of 2007, recent MIT graduate Drew Houston reached out to Ferdowsi to team up on an idea for cloud storage service that later became Dropbox. Ferdowsi dropped out of MIT in his last semester to commit himself fully to Dropbox, and worked with Houston out of a small office in Cambridge to build the platform.

As a teenager growing up in London, Branson struggled with dyslexia and did poorly in school. His school's headmaster once told Branson that he would either end up in prison or become a millionaire.

As a 15-year-old student still in secondary school, Branson produced a magazine called Student, and dropped out of school to work on the project. Although the magazine failed, he found success in a side hustle selling mail-order records, and turned the business into a successful company called Virgin Records.

Pittman grew up in Mississippi, and was already working as an announcer on the radio by the time he was 15 years old. He enrolled in nearby Millsaps College, but he didn't stay for long, and left school to pursue a career in radio. By 18, he was working at a radio station in Pittsburgh as a program director.

Karp never even finished high school in New York City — he dropped out at 14. Instead of heading to college, he entered the tech scene, and quickly became the chief technology officer for a now-defunct online messaging board called UrbanBaby that was bought by CNET in 2006.

Dell attended the University of Texas in 1983 as a premed student, but decided by the end of his freshman year that he wanted to drop out. In the summer before sophomore year, Dell sold $180,000 worth of reworked PC computers, which was enough to convince his parents he didn't have to go back to college.

By the time Rose enrolled as a computer science student at the University of Nevada, Las Vegas, he was already working as a technician at a nearby Department of Energy nuclear test site. He dropped out of school at the end of his sophomore year to head to the Bay Area.

Diller grew up in Beverly Hills, and attended UCLA in nearby Los Angeles for college. Diller said he lasted "literally, three weeks" at college before he dropped out, because he "wasn't interested or stimulated." Diller landed a job through a friend in the mail room at the talent agency William Morris, a gig that launched his career in the media industry.

Allen dropped out of Washington State University in 1974 after two years to work as a programmer in Boston, where his friend since grade school — Microsoft cofounder Bill Gates — was attending Harvard. Allen got a job offer from Honeywell, and moved to the Boston area with his then-girlfriend.

Gates left Harvard in 1975 to cofound Microsoft with longtime friend Paul Allen.

When Gates left school, he took it as an official leave of absence. Doing that allowed him to return to school "if things hadn't worked out."