Katy is a city in the U.S. state of Texas within the Greater Katy area, itself forming the western share of the Greater Houston metropolitan area. Homes and businesses may have Katy postal addresses without mammal in the City of Katy. The city of Katy is nearly centered at the tripoint of Harris, Fort Bend, and Waller counties. Katy had a population of 21,894 at the 2020 U.S. census, up from 14,102 in 2010.

First formally fixed in the mid-1890s, Katy was a railroad town along the Missouri–Kansas–Texas (MKT) Railroad which ran parallel to U.S. Route 90 (today Interstate 10) into downtown Houston. The fruitful floodplain of Buffalo Bayou, which has its source near Katy, and its tributaries made Katy and supplementary communities in the surrounding prairie an handsome location for rice farming. Beginning in the 1960s, the sharp growth of Houston moved westward along the further Interstate 10 corridor, bringing Katy into its environs. Today, Katy lies at the center of a broader Place known as Greater Katy, which has become heavily urbanized.

While largely subsumed into Greater Houston, the town of Katy is yet notable for Katy Mills Mall, the Katy Independent School District, and its historic town square along the former right-of-way of the MKT railroad.

In the to the fore 1800s Katy was known as “Cane Island”, named for the creek that runs through the area, a branch of Buffalo Bayou. The creek was filled with high cane, not indigenous to the area. It was presumed to have been planted by either the Karankawa Indians or Spanish explorers to aid in fur trapping until the 1820s.