John Victor Roos (born February 14, 1955) is an American businessman, attorney, and diplomat who served as United States Ambassador to Japan from 2009 to 2013.

Before accepting the ambassadorship from President Barack Obama, Roos was the CEO of Silicon Valley–based law firm of Wilson Sonsini Goodrich & Rosati.

The company caught the tech startup wave and over the next 25 years became the premier legal firm in the Valley, growing from 50 employees to more than 1,500 worldwide.

Roos played a key role in managing the relationship through that transition, as well as President Obama's rebalance to Asia, placing even more importance on the U.S.-Japan Alliance as the cornerstone of peace and security in the region.

Following the devastating 9.0 earthquake, tsunami, and nuclear crisis on March 11, 2011, Ambassador Roos led the American mission to support Japan's response to the multi-dimensional and unprecedented disaster.

Roos led the U.S. government's communication, and he used his Twitter feed to assure that the 155,000 Americans living in Japan received timely information about the disaster.

The Initiative represents a path-breaking paradigm in U.S. public diplomacy, in which government joins forces with private enterprises and organizations to achieve mutually beneficial, strategic goals.

TOMODACHI provides young Japanese and Americans with opportunities to study, live, and work in each other's countries, thereby ensuring a thriving bilateral partnership into the foreseeable future.

Roos marshaled assistance from a large number of high-profile celebrities to support the cause, including Lady Gaga, Tom Cruise, Will Smith, Cal Ripken, and will.i.am.

As of the end of 2016, TOMODACHI has impacted the lives of more than 5,700 young people in the United States and Japan through cultural exchanges and leadership training.

[20] Ambassador Roos' work with the TOMODACHI Initiative was recognized with the Special Gold Standard Award for Public Affairs Excellence in December 2012,[21] On September 22, 2014, Ambassador Roos was also awarded the Distinguished Public Service Award by Secretary of the Navy Ray Mabus for "his relentless efforts to forge a deeper bilateral security relationship between Japan and the United States," his "dynamic and steadfast leadership during Operation Tomodachi [that] paved the way for nearly 200 American ships and aircraft to transport essential relief supplies and equipment to the thousands left homeless after the March 2011 Tohoku earthquake and tsunami."

John Roos is the Founding Partner, Geodesic Capital, which supports U.S.-based entrepreneurs building transformative growth stage technology companies.