Turtlecreek Township is one of eleven townships of Warren County, Ohio. It is in the central part of the county and surrounds the county seat of Lebanon. It was named for the Turtle Creek, a stream named for Indian chief Little Turtle. Turtlecreek is the largest township in the county, originally containing sixty-three whole and seven fractional sections. It had a population of 12,617 in 2000, up from 10,383 in 1990.

It is bounded on the east by the Little Miami River (across the Little Miami is Washington Township), on the north by Wayne, Clearcreek, and Franklin Townships; on the east by the Butler County townships of Lemon and Liberty; and on the south by Deerfield and Union Townships. The city of Lebanon withdrew from the township in the 1960's and formed a paper township. Portions of the township have also been lost to annexations by the cities of Monroe, Middletown, and Mason.

Turtlecreek Township was established by the Warren County Commissioners on August 15, 1804, from parts of Deerfield and Clearcreek Townships. Part of Union Township and that portion of Salem Township north of the Little Miami River were part of Turtlecreek, Union being detached in 1815 and the trans-Miami section of Salem detached from Union in 1860.

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 first settlement in what was to become Warren County was at Beedle's Station in 1795. From 1805 until the early 20th century the township was the home of Union Village, one of the largest Shaker communities, located in the west central part of the township about midway between Monroe and Lebanon on State Route 63 and Mason and Red Lion on State Route 741. This is now the site of the Otterbein retirement community with a population of several hundred.

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

Both Interstate 75 and Interstate 71 cross the township, as do US Route 42 and State Routes 48, 63, 123, 350, and 741. The Warren County Airport is located in Turtlecreek Township on Greentree Road between Lebanon and Greentree Corners.

Most of the township is in the Lebanon City School District but a portion of the north center is in the Springboro Community City School District. The portion within the city of Monroe was detached circa 2002 and placed in the new Monroe Local School District. A part in the northwest is in the Middletown City School District, a part in the southwest is in the Mason City School District, and a part in the southeast is in the Little Miami School District.

Most of Turtlecreek Township is served by the Lebanon (45036) and Oregonia (45054) post offices, but parts are served by Middletown (45044), Monroe (45050), and Franklin (45005). Most of the township is in the Lebanon telephone exchange but parts are within the Mason, Franklin, Morrow, Monroe, and Middletown exchanges.