Abstract: Helmet mount apparatus provides a secure helmet holder for mounting a fireman helmet in a fire truck or other emergency vehicle. Three brim brackets, one of which is slidable on a base plate against a spring bias force, clamp the brim of the helmet between the brim brackets. The helmet can be mounted by positioning the brim into the slidable brim bracket and sliding the brim bracket far enough to allow inserting the brim also into the other two brim brackets, and then releasing the helmet to allow the spring bias to clamp the helmet onto the mount apparatus.