Tillamook County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 27,390. The county seat is Tillamook. The county is named for the Tillamook or Killamook people, a Native American tribe who were living in the area in the early 19th century at the time of European American settlement. The county is located within Northwest Oregon.

The city of Tillamook is the county seat of Tillamook County, Oregon, United States. The city is located on the southeast end of Tillamook Bay on the Pacific Ocean. The population was 5,231 at the 2020 census.