Gilbert is a town in Maricopa County, Arizona, United States. Located southeast of Phoenix, Gilbert is home to 288,128 residents. It is the fifth-most populous municipality in Arizona and is considered a suburb of Phoenix.

Incorporated on July 6, 1920, Gilbert was once known as the "Hay Shipping Capital of the World".

Gilbert was established by William "Bobby" Gilbert, who provided land to the Arizona Eastern Railway in 1902 to construct a rail line between Phoenix and Florence, Arizona. Ayer's Grocery Store, Gilbert's first store, opened in 1910 and became the location of the first post office in 1912. The post office moved several times before settling on the east side of Gilbert Road in downtown, where it stands today. In 1912, many Mormons who had fled the Mormon colonies in Mexico due to the actions of Pancho Villa's forces settled in Gilbert. By 1915, they began holding church meetings at the Gilbert Elementary School. In 1918, they were organized into the Gilbert Ward.

Incorporated on July 6, 1920, Gilbert was primarily a farming community fueled by the rail line and construction of the Roosevelt Dam and the Eastern and Consolidated Canals. It remained an agricultural town for many years and was known as the "Hay Capital of the World" from 1911 until the late 1920s.

Gilbert is in the southeastern Phoenix metropolitan area. It is south of Mesa, northeast of Chandler, and northwest of Queen Creek.

According to the United States Census Bureau, the town has an area of 68.86 square miles (178.35 km²), of which 68.65 square miles (177.80 km²) is land and 0.20 square miles (0.52 km²) is water.

Gilbert has a subtropical, hot desert climate (Köppen climate classification BWh) with dry and hot summers, and mild to warm winters, with little rainfall.

As of the 2020 census, there were 267,918 people, 88,896 households, and 69,603 families residing in the town. There were 93,230 housing units.