Kings Park is a hamlet and census-designated place (CDP) in the Town of Smithtown, in Suffolk County, in Long Island, in New York, United States. The population was 17,085 as of the 2020 census.

According to the United States Census Bureau, the CDP has a total area of 6.6 square miles (17.1 km²), of which 6.2 square miles (16.1 km²) is land and 0.39 square miles (1.0 km²), or 5.93%, is water.

Kings Park is bordered by Nissequogue to its east across the Nissequogue River, by Fort Salonga to its west, by Commack to its southwest, and by the hamlet of Smithtown to its southeast.

The CDP also includes part of the hamlet of San Remo. Located on the Northeastern part of the hamlet

As of the 2020 census, Kings Park had a population of 17,085. The median age was 47.4 years. 18.5% of residents were under the age of 18 and 21.2% of residents were 65 years of age or older. For every 100 females there were 93.6 males, and for every 100 females age 18 and over there were 91.4 males age 18 and over.

99.9% of residents lived in urban areas, while 0.1% lived in rural areas.

There were 6,311 households in Kings Park, of which 28.1% had children under the age of 18 living in them. Of all households, 56.4% were married-couple households, 15.0% were households with a male householder and no spouse or partner present, and 24.5% were households with a female householder and no spouse or partner present. About 24.7% of all households were made up of individuals and 14.4% had someone living alone who was 65 years of age or older.

There were 6,564 housing units, of which 3.9% were vacant. The homeowner vacancy rate was 1.0% and the rental vacancy rate was 4.3%.