Alexis Kerry Ohanian (born April 24, 1983), also known by the username kn0thing, is an American Internet entrepreneur and investor. He is best known as the co-founder and executive chairman of the social news website Reddit. He also co-founded the early-stage venture capital firm Initialized Capital, helped launch the travel search website Hipmunk, and started the social enterprise Breadpig. He was also a partner at Y Combinator. In 2012, Andy Greenberg of Forbes magazine dubbed him "Mayor of the Internet."

Ohanian is based in Florida, where he lives with his wife, tennis player Serena Williams, and their daughter.

Ohanian was born in Brooklyn, New York, to a German mother, Anke (née Prigge), and an Armenian father, Chris Ohanian. Chris's grandparents came to the US as refugees after the Armenian Genocide. Alexis went to Howard High School in Ellicott City, Maryland, where he gave the student address for his graduating class in 2001.

After graduation from the University of Virginia in 2005 with degrees in commerce and history, Ohanian and friend Steve Huffman pitched the idea MyMobileMenu to Y Combinator. The company passed on the idea, but encouraged the duo to come up with another idea it could potentially fund. They subsequently came up with reddit.com with the goal of it becoming the "front page of the Internet." Living in Boston at the time, they were less than a month into development when Ohanian learned that his girlfriend had fallen five stories and was in a coma. Shortly after,his father called him to tell him that his mother had been diagnosed with an inoperable tumor.

Reddit joined Y-Combinator's first batch of start-ups in the Summer of 2005 and were later acquired by Condé Nast in 2006 for an undisclosed amount between 10–20 million dollars. Ohanian continued to work closely with Reddit as a member of its board of directors. He returned to Reddit full-time with co-founder Huffman on July 10, 2015 to lead the now-independent company. He stepped back from the company in February 2018 to return to focusing on investing.

In 2007, Ohanian launched Breadpig, an "uncorporation" that produces geeky merchandise and gives the proceeds to charity. He no longer is involved in the day-to-day operations of Breadpig.

In 2009, Ohanian spoke at TED about a whale named Mister Splashy Pants. After leaving Reddit in 2010, Ohanian spent three months working in micro-finance as a Kiva fellow in Yerevan, Armenia. Ohanian helped launch travel search website Hipmunk in 2010, and now acts as an adviser. In June 2010, Ohanian announced the launch of his company Das Kapital Capital, which focuses on startup investing, advising and consulting.

Ohanian was named the "Ambassador to the East" for early stage venture firm Y Combinator. In this position, he meets with East Coast applicants, mentors New York YC founders, and is a general representative for the company. He also held the role of part-time partner and full-time partner at Y Combinator, before leaving in 2016 to help launch the third Initialized Capital fund with Garry Tan.