Klein is an unincorporated community in Harris County, Texas, United States, roughly bordering Texas State Highway 99 to the north, Texas State Highway 249 to the west, Interstate 45 to the east, and the city of Houston to the south. It includes the entire area of Klein ISD. Residents of the zip codes 77066, 77069, 77086, 77379, 77388, 77389 and 77391 can use Klein as their postal city. Klein is one of the most diverse, as well as being one of the largest unincorporated areas of Houston.
It is named after Adam Klein, a German immigrant whose best-known great-great-grandson is singer Lyle Lovett. Other famous sons and daughters of the Klein community include actor Jim Parsons, actor Lee Pace, actor Matthew Bomer, actress Lynn Collins, actress Sherry Stringfield, singer/songwriter Derek Webb, songwriter Aaron Tate, singer/songwriter Chase Hamblin, actor Ben Rappaport, Major League Baseball players David Murphy and Josh Barfield, NFL players Randy Bullock, Ashton Youboty, Mike Green (running back), and Olympic gold medalists Laura Wilkinson, Simone Biles, and Chad Hedrick as well as Kevin M. Klein chef and restaurateur 
Klein is served by David Wayne Hooks Memorial Airport, one of just a few privately owned airports in the U.S. to have a Federal Aviation Administration control tower, and home to Civil Air Patrol’s Delta Composite Squadron.