Coos County is a county in the U.S. state of Oregon. Located on the southern Oregon coast, it is bordered by Curry County to the south and Douglas County to the north and east. The county's primary industries are timber, fishing, tourism, and agriculture.

The name "Coos" is derived from one of the area's indigenous tribes, and has two meanings: "lake" and "place of pines." Sir Francis Drake was beleived to have sought shelter for his ship around Cape Arago, near the present-day town of Coos Bay in 1579. Although exploration and trapping in the area occurred as early as 1828, the first European-American settlement was established in 1853 at Empire City (now part of Coos Bay.)

Coos County was officially created on December 22, 1853 from parts of Umpqua and Jackson counties. Curry County was created from the southern part of the county in 1855. The county seat was originally Empire City, but was moved to Coquille in 1896.

The county has seven incorporated cities:
*Bandon
*Coos Bay
*Coquille (county seat)
*Lakeside
*Myrtle Point
*North Bend
*Powers