Judith "Judy" L. Estrin (born 1954 or 1955) is an Internet pioneer and American business executive. Former colleague Richard A. Karp credits Estrin as one of the key people in the development of Internet when they worked together with Vint Cerf on the initial TCP-project at Stanford.
She is now CEO of JLabs(formerly called Packet Design Management Company), a privately held company focused on furthering innovation in business, government and non-profit organizations. Estrin is the author of "Closing the Innovation Gap: Reigniting the Spark of Creativity in a Global Economy" (McGraw-Hill; Hardcover, September 2008), a general interest book that challenges national, academic and business leaders to work together to make USA competitive again. Estrin is a serial entrepreneur who co-founded eight technology companies. She was the CTO of Cisco Systems from 1998 to 2000. Estrin served on the boards of FedEx Corporation (1989–2010), Rockwell Automation and Sun Microsystems, as well as on the Board of Directors of the Walt Disney Company for fifteen years. She also serves on the advisory boards of Stanford’s School of Engineering and Bio-X interdisciplinary program, and is a member of the University of California President’s Science and Innovation Advisory Board. She also served on the America Compete's Innovation Advisory Board in 2011.
Estrin's high tech family includes sister Deborah Estrin, a professor of Computer Science  and parents, Thelma and Gerald Estrin, who were both computer scientists at UCLA. Her son, David Carrico, is also a tech entrepreneur, who founded EvntLive, which later Estrin joined as CEO.
While at Stanford, Estrin worked with the research group headed by Vint Cerf, a computer science pioneer often called the "Father of the Internet". Cerf's team developed the TCP/IP specification which forms the underlying technology of the Internet.
After Stanford she worked at Zilog Corporation, where she contributed to the design of the Z8 and Z8000 microprocessors  and led the team that developed one of the first commercial local area network systems  called Z-net.
In 1981, Estrin co-founded Bridge Communications — a network router, bridges, and communications servers company that went public in 1985 and merged with 3Com in 1987. In 1988 she joined the founding team of Network Computing Devices (NCD) as Executive Vice President, later becoming President and CEO in 1993. 
In 1995, she co-founded Precept Software, Inc., a developer of networking software company, and served as President and CEO until its acquisition by Cisco Systems in 1998, when she became its CTO and Senior Vice President of Cisco Systems until 2000.
In 2000, Estrin co-founded Packet Design, LLC, a networking technology company, with her husband Bill Carrico, with $24 million in funding from the venture firm Foundation Capital and a group of private investors, including Estrin; Carrico; James Barksdale; Bill Joy, and Frank Quattrone. Packet Design later spun out three venture backed start-ups, including Packet Design, Inc. She served as Packet Design, LLC’s CEO until it was dissolved, distributing its assets to investors in late 2007.
She served as a member of the boards of directors of The Walt Disney Company from 1998 until 2014, FedEx Corporation from 1989 until 2010, Sun Microsystems from 1995 through 2003 and Rockwell Corporation from 1994 through 1998. In addition, she sits on the advisory councils of Stanford's School of Engineering.
- 2010 GIL (Growth, Innovation and Leadership) Award from Frost & Sullivan
- 2002 Women in Technology International Hall of Fame.
- 1998: 50 most powerful women in American business
- 1987: EY Entrepreneur of the Year Award Recipient, Northern California Region.
- "Ranking The 50 Most Powerful Women FORTUNE'S FIRST ANNUAL LOOK AT THE WOMEN WHO MOST INFLUENCE CORPORATE AMERICA". archive.fortune.com. October 12, 1998. Retrieved 2014-03-04.
Judith Estrin, 43
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- "Meet the Innovation Advisory Board". commerce.gov. Archived from the original on 2012-01-11. Retrieved 2014-03-04.
- "Deborah Estrin". tech.cornell.edu. Retrieved 2014-03-04.
- "‘An Excellent Match:’ How Deborah Estrin, First Prof Chosen for CornellNYC Tech, Was Drawn to Roosevelt Island". cornellsun.com. August 30, 2012. Retrieved 2014-03-04.
- "‘With $2.3M From Vint Cerf & More, Tech Pioneer Judy Estrin Unveils EvntLive, The Web’s New Interactive Concert Hall". techcrunch.com. February 6, 2013. Retrieved 2014-03-04.
- "Oral History Panel on the Development and Promotion of the Zilog Z8000 Microprocessor" (PDF). archive.computerhistory.org. Retrieved 2014-03-04.
- "Mike Throm's memories of Zilog". old-computers.com. Retrieved 2014-03-04.
- "Z-NET a microprocessor based local network by Judy Estrin". dl.acm.org. 1980. Retrieved 2014-03-04.
- "2002 Women in Technology Hall of Fame". prnewswire.com. Retrieved 2014-03-04.
- "Cisco Systems Appoints Judith Estrin as Chief Technology Officer,Cisco Systems press release, March 11, 1998". newsroom.cisco.com. Retrieved 2014-03-04.
- "Cisco Systems press release, April 3, 2000". newsroom.cisco.com. Archived from the original on 2001-11-29. Retrieved 2014-03-04.
- "Estrin Startup To Address Infrastructure Concerns". forbes.com. June 13, 2000. Retrieved 2014-03-04.
- "Packet Design". layer8solutions.ca. Retrieved 2014-03-04.
- "Judy Estrin". keyspeakers.com. Retrieved 2014-03-04.
- "Silicon Valley Pioneer Judy Estrin to Receive 2010 GIL (Growth, Innovation and Leadership) Award from Frost & Sullivan". prnewswire.com. July 8, 2010. Retrieved 2014-03-04.
- Estrin, Judy. "Nature or Nurture: My Life in Technology, So Far", Computer History Museum
- Estrin, Judy, Closing the Innovation Gap: Reigniting the Spark of Creativity in a Global Economy, McGraw-Hill, September, 2008
- Women Who Inspire Us, Judy Estrin
- Alumni profile: Judith Estrin, Stanford University.
- Speaking at Stanford
- Podcast Interview as one of NCWIT's Entrepreneurial Heroes
- Closing the Innovation Gap