Cameron Howard Winklevoss (born August 21, 1981) is an American cryptocurrency investor, former Olympic rower, and cofounder of Winklevoss Capital Management and Gemini cryptocurrency exchange. He competed in the men's pair rowing event at the 2008 Summer Olympics with his rowing partner and identical twin brother, Tyler Winklevoss. Winklevoss and his brother are known for co-founding HarvardConnection (later renamed ConnectU) along with Harvard classmate Divya Narendra. In 2004, the Winklevoss twins sued Facebook founder Mark Zuckerberg, claiming he stole their ConnectU idea to create the social networking site Facebook. In addition to ConnectU, Winklevoss also co-founded the social media website Guest of a Guest with Rachelle Hruska.

Cameron Howard Winklevoss was born on August 21, 1981, in Southampton, New York, and raised in Greenwich, Connecticut. He is the son of Carol (née Leonard) and Howard Winklevoss. Howard was an adjunct professor of actuarial science at the Wharton School of the University of Pennsylvania. At an early age, he (left-handed) and his identical "mirror-image" twin brother Tyler (right-handed) demonstrated a pattern of teamwork, building Lego together and playing musical instruments. At the age of 13, they taught themselves HTML and started a web-page company, which developed websites for businesses.

Winklevoss went to the Greenwich Country Day School before attending the Brunswick School for high school. He showed a fondness for the classics in high school, studying Latin and Ancient Greek. During his junior year, he co-founded the crew program with his brother.

On June 14, 2002, Winklevoss's older sister, Amanda, died from cardiac arrest induced by drug overdose.

He enrolled at Harvard University in 2000 for his undergraduate studies where he majored in economics, earning an AB degree and graduating in 2004. At Harvard, he was a member of the men's varsity crew, the Porcellian Club and the Hasty Pudding Club.

In 2009, Winklevoss entered the Saïd Business School at the University of Oxford where he obtained an MBA in 2010. While at Oxford he was an Oxford Blue, and rowed, in a losing effort, in the Blue Boat in the 156th Oxford-Cambridge Boat Race.

In December 2001, Winklevoss, along with his brother Tyler Winklevoss and fellow Harvard classmate Divya Narendra, sought a better way to connect with fellow students at Harvard University and other universities. The three conceived of a social network for Harvard students named HarvardConnection; the concept ultimately expanded to other schools around the country. What made ConnectU different from other social media platforms was the need to have a specific domain that matched the 'club' you were getting into, like harvard.edu. The idea was to make each school its own club, in which students could connect and be exclusive, similar to the infamous final clubs at Harvard. In January 2003, they enlisted the help of fellow Harvard student, programmer and friend Sanjay Mavinkurve to begin building HarvardConnection. Mavinkurve commenced work on HarvardConnection but departed the project in spring 2003 when he graduated and went to work for Google.

After the departure of Mavinkurve, the Winklevosses and Narendra approached Narendra's friend, Harvard student and programmer Victor Gao, to work on HarvardConnection. Gao, a senior in Mather House, opted not to become a partner in the venture, instead agreeing to be paid in a work for hire capacity. He was paid $400 for his work on the website code during the summer and fall of 2003, when he left the project.