Pecos may refer to:
- Pecos Bill, a mythical American cowboy, immortalized in numerous tall tales
- Pecos Classification, a division of all known Ancient Pueblo Peoples culture into chronological phases
- Pecos County, Texas, a county located in the U.S. state of Texas, named for the Pecos River
- Pecos National Historical Park, a National Historical Park in the U.S. state of New Mexico
- Pecos Pueblo, a National Historic Landmark in Pecos National Historical Park
- Pecos, New Mexico, a village in San Miguel County, New Mexico, United States
- Pecos River, rises near Santa Fe, New Mexico, United States
- Pecos, Texas, a city in Reeves County, Texas, United States
- USS Pecos, the name of two ships of the United States Navy
- USNS Pecos (T-AO-197), a U.S. Navy fleet replenishment oiler in service since 1989.