Gardner is a city in Johnson County, Kansas, United States.

Four years after its establishment, it became the first community in Johnson County—and perhaps the first in the state—to experience an attack by Confederate forces.

The headwaters of Kill Creek, which runs north joining with the Kansas River in De Soto, are also in Gardner.

The climate in this area is characterized by hot, humid summers and generally mild to cool winters.

[13] The 2020 United States census counted 23,287 people, 8,005 households, and 5,938 families in Gardner.

There were 8,294 housing units at an average density of 711.2 per square mile (274.6/km2).

20.4% of households consisted of individuals and 6.9% had someone living alone who was 65 years of age or older.

There were 7,300 housing units at an average density of 721.3 per square mile (278.5/km2).

20.1% of all households were made up of individuals, and 5% had someone living alone who was 65 years of age or older.

There were 3,533 housing units at an average density of 713.8 per square mile (275.6/km2).

19.5% of all households were made up of individuals, and 5.6% had someone living alone who was 65 years of age or older.

BNSF Railway built a refueling plant and office in Edgerton which is 3 miles from western Gardner.

The city council is made up of five (5) at-large members, each of whom serve rotating 4-year terms.

[33] The Gardner Police Department is contracted with USD 231 to provide school resource officer services.

The Johnson County Library maintains a branch in Gardner.