Santee is a city in San Diego County, California, United States. The population was 60,037 at the 2020 census. It is a part of the East County region. The city is bisected by the San Diego River, a linear greenbelt that includes parks, trails and more than 1,100 acres (450 ha) of natural habitat.

The region was the homeland of the Kumeyaay people. These original residents established the village of Sinyeweche on the banks of the San Diego River in the present-day Santee area.

In 1877, George A. Cowles, a pioneer rancher and businessperson, purchased 4,000 acres (1,600 ha) to develop his vineyards. The area became known as Cowlestown and was linked to the Cuyamaca Railroad. Three years after Cowles' death in 1887, his widow Jennie married Milton Santee. According to historian Harriette Wade, Jennie "lobbied hard" to rename Cowlestown to Santee in honor of her new husband, and a "reluctant vote of the citizens" approved the change in 1893.

In 1980, residents voted in favor of incorporation after voting against it three years earlier, giving rise to the city of Santee.

Santee shares the northern part of a valley with the city of El Cajon. The city is bisected by the San Diego River, which flows east to west for approximately 4.2 miles (6.8 km) within the city limits. Hills form a natural barrier on its northern and western sides.

At an altitude of 1,198 feet (365 m), Rattlesnake Mountain is the highest point in Santee. Rattlesnake Mountain is home to the Sky Ranch community, and is topped with a large illuminated star during the holiday season.^{[citation needed]}

According to the Köppen Climate Classification system, Santee has a semi-arid climate, abbreviated BSk on climate maps.

As of the 2020 census, Santee had a population of 60,037. The median age was 39.0 years. 22.3% of residents were under the age of 18 and 15.8% of residents were 65 years of age or older. For every 100 females there were 91.6 males, and for every 100 females age 18 and over there were 88.4 males age 18 and over.