James W. Breyer is an American venture capitalist and partner of Accel Partners, President of Accel Management Company, and founder/CEO of Breyer Capital, a global diversified investment firm.

Breyer graduated from Stanford University in 1983, with a BS degree in computer science and economics. Breyer then worked as a management consultant for McKinsey & Co., in New York. He earned an MBA from Harvard University, where he was named a Baker Scholar.^{[citation needed]}

Breyer is on the Board of Directors of Wal-Mart Stores, Inc,^{[non-primary source needed]} where he is the Lead/Presiding Independent Director, and Chairman of the Strategic Planning Committee. He also served on the Board of Marvel Entertainment until their acquisition by Disney,^{[citation needed]} where he was the founding Chairman of the Strategic Planning and Finance Committee. He is also on the board of Dell Inc..

Breyer is the former chairman of the National Venture Capital Association (NVCA), a former president of the Western Association of Venture Capitalists, and on the Board of the Associates of the Harvard Business School, Pacific Community Ventures, Stanford Technology Ventures Program, Technet, and a trustee of the San Francisco Museum of Modern Art (SFMOMA), and of The Menlo School.^{[non-primary source needed]} He is a minority owner of the Boston Celtics. Breyer is chairman of the Stanford Engineering Venture Fund, former chairman of the Harvard Business School California Research Center, and is the former chairman of the Silicon Valley region committee for Stanford University's Campaign for Undergraduate Education. He is also a member of various World Economic Forum committees, and a member of the Lead Director Network. In December 2005, Breyer was appointed an honorary professor at the Yuelu Academy, Hunan University, China. Breyer is also the chief executive officer of Breyer Capital, a venture capital and investment firm.