Siesta Key is a barrier island off the southwest coast of the U.S. state of Florida, located between Roberts Bay and the Gulf of Mexico. A portion of it lies within the city boundary of Sarasota, but the majority of the key is a census-designated place (CDP) in Sarasota County. Siesta Key is part of the North Port–Bradenton–Sarasota, Florida Metropolitan Statistical Area.

From the 19th century to the early 20th century, Siesta Key was known by a variety of names, including Little Sarasota Key and Sarasota Key. The first attempts to develop the key were by the Siesta Land Company in 1907, consisting of Harry Higel, Captain Louis Roberts, and E. M. Arbogast. The company platted the northern end of the key as Siesta on the Gulf of Mexico as well as dredged bayous and built docks.

Access to Siesta Key was by boat or ferry until the first bridge connecting it to the mainland was completed in 1917. The bridge was replaced in 1927 with the addition of a second bridge located on the southern end of the key. The entire key officially was recognized as Siesta Key by 1952.

On October 9, 2024, Hurricane Milton made landfall as a Category 3 hurricane near Siesta Key.

According to the United States Census Bureau, the CDP has a total area of 3.5 square miles (9.0 km), of which 2.4 square miles (6.1 km) is land and 1.1 square miles (2.9 km), or 32.08%, is water.

Siesta Key is made up of four main districts: Siesta Beach, Crescent Beach, Turtle Beach, and Siesta Key Village. It contains a suburban residential area located on the Siesta Key barrier island on the West coast of Florida, just west of the town of Sarasota. The community on Siesta Key consists of single-family homes, condominiums, retail shops, and art galleries.

Beaches on Siesta Key include Siesta Beach, Crescent Beach, and Turtle Beach.

Historical population

Census	Pop.	Note	%±
1970	4,460		—
1980	7,010		57.2%
1990	7,772		10.9%
2000	7,150		−8.0%
2010	6,565		−8.2%
2020	5,454		−16.9%
source:

As of the 2020 United States census, Siesta Key CDP had a population of 5,454 with 2,948 households.

The population was split by age, with 1.0% under 5 years old, 6.5% under 18, and 54.9% were 65 years and older. 51.2% were female persons.

By race, the population was split with 93.6% white, 0.4% American Indian or Alaska Native, 1.8% were Asian, 3.6% were two or more races, and 2.7% were Hispanic or Latino.

The median household income was $108,527. 3.3% of the population lived below the poverty threshold. 98.7% of households had a computer, and 91.3% of households had a broadband internet subscription.

11.8% of the population were foreign-born persons. There were 483 veterans living in the CDP.

• Frederick Fennell (1914-2004), noted band conductor and musical educator.

• Explore Sarasota and Vicinity, Kenneth F. Tricebock, 1988

• Siesta Key Chamber of Commerce
• Sarasota County government