Willowbrook is a city in Reno County, Kansas, United States.

According to the United States Census Bureau, the city has a total area of 0.31 square miles (0.80 km2), all of it land.

There were 35 housing units at an average density of 112.9 per square mile (43.6/km2).

5.7% of all households were made up of individuals, and 5.8% had someone living alone who was 65 years of age or older.

No households were made up of individuals, and none had someone living alone who was 65 years of age or older.

The community is served by Nickerson–South Hutchinson USD 309 public school district.