Breathing mask assemblies that include adjustable forehead supports are disclosed herein. In one embodiment, a forehead support is adjustably coupled to a central or main body of the breathing mask. A clamp is configured to lock the position of the forehead support relative to the central body and to lock forehead support at multiple different positions. In one exemplary embodiment, the forehead support may be locked at any position along a path of travel between a first position and a second position.