Turtlecreek Township is one of the eleven townships of Warren County, Ohio, United States. It is in the central part of the county and surrounds the county seat of Lebanon. Turtlecreek is the largest township in the county, originally containing sixty-three whole and seven fractional sections. The population was 17,644 as of the 2020 census.

Located in the central and western parts of the county, it borders the following townships:

The city of Lebanon withdrew from the township in the 1960s and formed a paper township. Portions of the township have also been lost to annexations by the cities of Monroe, Middletown, and Mason. Those areas within Monroe, however, remain in the township.

Most of the township was in the Symmes Purchase, but the two northernmost rows of sections were not, though they are surveyed in the same manner as the Purchase.

The township is named for the Turtle Creek, a stream named for Indian chief Little Turtle. It is the only Turtlecreek Township statewide, although there is a Turtle Creek Township in Shelby County.

Turtlecreek Township was established by the Warren County Commissioners on August 15, 1804.

The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1. Two are elected in the year after the presidential election and one is elected in the year before it. There is also an elected township fiscal officer, who serves a four-year term beginning on April 1 of the year after the election, which is held in November of the year before the presidential election. Vacancies in the fiscal officership or on the board of trustees are filled by the remaining trustees.

There are two large state prisons located in the western part of the township: Lebanon Correctional Institution and Warren Correctional Institution.