Walla Walla is the largest city in and the county seat of Walla Walla County, Washington, United States. The population of the town itself was 31,731 at the 2010 census. The population of Walla Walla and its two suburbs, the town of College Place and unincorporated "East Walla Walla," is about 45,000. Walla Walla is in the southeastern region of Washington, approximately four hours by car from Portland, Oregon, and Seattle, Washington, and thirteen miles north of the Oregon border.

Whitman College, Walla Walla Community College, and the Washington State Penitentiary are located in Walla Walla. Walla Walla University is located in nearby College Place, Washington. Baker Boyer Bank, the oldest bank in the state of Washington, was founded in Walla Walla in 1869.

Walla Walla has received many civic awards since 2000. In 2001 Walla Walla was a Great American Main Street Award winner for the transformation and preservation of its once dilapidated main street. In July 2011, USA Today selected Walla Walla as the friendliest small town in the United States. Walla Walla was also named Friendliest Small Town in America the same year as part of Rand McNally's annual Best of the Road contest. In 2012 and 2013 Walla Walla was a runner-up in the best food category for the Best of the Road.

Walla Walla is famous for its sweet onions, and, more recently, wine. There are more than 100 wineries in or near Walla Walla.