Kalmiopsis Wilderness is a wilderness area in the Klamath Mountains of southwestern Oregon, within the Rogue River – Siskiyou National Forest. It was designated wilderness by the United States Congress in 1964 and now comprises a total of 179,755 acres. There are approximately 153 miles of trails on 24 established hiking trails in the area.
The Kalmiopsis Wilderness was named for Kalmiopsis leachiana, a slow-growing plant related to the rhododendron, which was discovered in the area in 1930.
Elevations in Kalmiopsis Wilderness range from 500 to 5,098 feet, at Pearsoll Peak. The area is characterized by deep, rough canyons, sharp rock ridges, and clear, rushing mountain streams and rivers. The wilderness includes the headwater basins of the Chetco, North Fork Smith Rivers, as well as part of the Illinois River canyon. All three of these rivers have been designated Wild and Scenic.

In 2002, the nearly 500,000-acre Biscuit Fire burned the entire wilderness area. The environment has changed dramatically and provides a unique opportunity to observe a natural response to fire disturbance through plant succession, erosional and depositional occurrences and changed habitat for flora and fauna.