Mark Elliot Zuckerberg (/ˈzʌkərbɜːrɡ/; born May 14, 1984) is an American businessman and programmer who co-founded the social media service Facebook and its parent company Meta Platforms. He is Meta's chairman, chief executive officer, and controlling shareholder.

Zuckerberg briefly attended Harvard College, and launched Facebook there in February 2004 with his roommates Eduardo Saverin, Andrew McCollum, Dustin Moskovitz and Chris Hughes. Zuckerberg took the company public in May 2012 with majority shares. He became the world's youngest self-made billionaire in 2008, at age 23, and has consistently ranked among the world's wealthiest individuals. According to Forbes, Zuckerberg's estimated net worth stood at US$251 billion as of October 2025, making him the third-richest person in the world.

He has used his funds to organize multiple large donations, including the establishment of the Chan Zuckerberg Initiative. A film based on Zuckerberg's early career, legal troubles and initial success with Facebook, The Social Network, was released in 2010 and won multiple Academy Awards. His prominence and fast rise in the technology industry has prompted political and legal attention. He has been the subject of multiple lawsuits regarding the creation and ownership of the website as well as issues such as user privacy.

Mark Elliot Zuckerberg was born on May 14, 1984, in White Plains, New York, to Jewish parents Dr. Edward Zuckerberg, a dentist, and Karen (née Kempner), a psychiatrist. He and his three sisters (Arielle, Randi, and Donna) were raised in a Reform Jewish household in Dobbs Ferry, New York. Their great-grandparents were emigrants from Austria, Germany, and Poland. Zuckerberg initially attended Ardsley High School before transferring to Phillips Exeter Academy. He was captain of the fencing team.

Zuckerberg learned computer programming in his childhood. At about the age of eleven, he created "ZuckNet", a program that allowed computers at the family home and his father's dental office to communicate with each other. During Zuckerberg's high-school years, he worked to build a music player called the Synapse Media Player. The device used machine learning to learn the user's listening habits, which was posted to Slashdot and received a rating of 3 out of 5 from PC Magazine. The New Yorker once said of Zuckerberg, "some kids played computer games. Mark created them." While still in high school, he attended Mercy College taking a graduate computer course on Thursday evenings.

The New Yorker noted that by the time Zuckerberg began classes at Harvard in 2002, he had already achieved a "reputation as a programming prodigy". He studied psychology and computer science, resided in Kirkland House, and belonged to Alpha Epsilon Pi. In his second year, he wrote a program that he called CourseMatch, which allowed users to make class selection decisions based on the choices of other students and help them form study groups. Later, he created a different program he initially called Facemash that let students select the best-looking person from a choice of photos. Arie Hasit, Zuckerberg's roommate at the time, explained:

We had books called "Face Books", which included the names and pictures of everyone who lived in the student dorms. At first, he built a site and placed two pictures, or pictures of two males and two females. Visitors to the site had to choose who was "hotter" and according to the votes there would be a ranking.

The site went up over a weekend, but by Monday morning, the college shut it down, because its popularity had overwhelmed one of Harvard's network switches, preventing students from accessing the Internet. In addition, many students complained that their photos were being used without permission. Zuckerberg apologized publicly, and the student paper ran articles stating that his site was "completely improper".