District 18 of the Texas Senate is a senatorial district that currently serves all of Aransas, Austin, Burleson, Calhoun, Colorado, DeWitt, Fayette, Goliad, Gonzales, Jackson, Lavaca, Lee, Matagorda, Refugio, Victoria, Waller, Washington and Wharton counties, western portions of Fort Bend and Harris counties, and an eastern precinct of Nueces County in the U.S. state of Texas. The current Senator from District 18 is Lois Kolkhorst.