Peter Andreas Thiel is an American entrepreneur, venture capitalist, and political activist. He is best known as a co-founder of PayPal, Palantir Technologies, and Founders Fund. Thiel was also the first outside investor in Facebook.

Thiel's career began in the legal and finance sectors, working as a securities lawyer at Sullivan & Cromwell, a speechwriter for former U.S. Secretary of Education William Bennett, and a derivatives trader at Credit Suisse. In 1996, he founded Thiel Capital Management and later co-founded PayPal with Max Levchin and Luke Nosek in 1998. As PayPal's chief executive officer, Thiel led the company until its sale to eBay in 2002 for $1.5 billion.

Following PayPal, Thiel founded Clarium Capital, a global macro hedge fund. In 2003, he launched Palantir Technologies, a big data analysis company, and has served as its chairman since its inception. In 2005, alongside PayPal partners Ken Howery and Luke Nosek, he launched Founders Fund. Thiel became Facebook's first outside investor in 2004, acquiring a 10.2% stake for $500,000, and sold the majority of his shares in 2012 for over $1 billion but remains on the board of directors.

Throughout his career, Thiel has co-founded various ventures, including Valar Ventures, Mithril Capital, and was a part-time partner at Y Combinator from 2015 to 2017.

Thiel is known for his conservative libertarian views and has made significant contributions to right-wing political figures and causes in the United States. He was controversially granted New Zealand citizenship in 2011 despite limited residency.

In philanthropy, through the Thiel Foundation, he governs the grant-making bodies Breakout Labs and Thiel Fellowship, which support non-profit research in areas like artificial intelligence, life extension, and seasteading. In 2016, Thiel gained attention for funding Hulk Hogan in the Bollea v. Gawker lawsuit, which resulted in Gawker's bankruptcy.