Fort Walton Beach is a city located in southern Okaloosa County, Florida, within the United States. Situated on the Emerald Coast region, it serves as a principal city of the Crestview−Fort Walton Beach−Destin Metropolitan Statistical Area. The municipality lies along the Santa Rosa Sound and includes portions of what was formerly Tower Beach on Santa Rosa Island, now known as Okaloosa Island.

The area's prehistoric settlement is attributed to the Fort Walton Culture, which flourished from approximately 1100 to 1550 CE. Early European contact occurred in 1528, though permanent settlements were established later by early settlers of Walton County. The community was originally named Anderson before appearing as Camp Walton on maps in 1911, serving as a Confederate Army camp during the Civil War.

The United States Post Office changed the official name from Camp Walton to Fort Walton in 1932, with the city incorporating in 1941. The name was officially changed to Fort Walton Beach in 1953, incorporating the former Tower Beach amusement area. The landscape features the Indian Temple Mound and Museum, a historic site reflecting the region's complex indigenous heritage and mound-building traditions.

As a year-round fishing and beach resort community, the city attracts visitors primarily during the busy summer season. Key attractions include the Gulfarium, the Air Force Armament Museum at Eglin Air Force Base, and the Billy Bowlegs Festival held in June. The downtown area features antique stores along Highway 98, while the Miracle Strip Parkway provides access to coastal amenities.

The population was 20,922 as of the 2020 census. The local economy benefits significantly from tourism, supported by nearby Destin-Fort Walton Beach Airport and major highways like US 98 and State Road 85. The climate is humid subtropical, characterized by hot summers and mild winters, with rare snowfall events such as the significant blizzard in January 2025.