An embodiment of an adjustable cervical collar system includes a collar body and a chin support structure assembled together, about respective pivots at opposed ends, for pivotal movement about a pivot axis so that the angle subtended by the collar body and chin support structure can be adjusted. The collar body and chin support structure can be locked in a selected position by a locking mechanism. A release mechanism permits the wearer to release the locking mechanism using one hand, and the angular position of the chin support structure relative to the collar body is changed manually. When the release mechanism is released, the locking mechanism automatically locks the chin support in the new position. A neck strap is detachable from the chin support structure and the collar body, and its length is also adjustable.
