A safety housing for a firearm includes a biometric or other access authentication device, an enclosure, a frame assembly, a slide assembly, and a door. The frame and the slide assemblies nest within the enclosure, the frame assembly affixes to the enclosure, and the slide assembly moves relative to the frame assembly. The door moves between an open position in which the firearm is removable through an access opening in the housing, and a closed position covering the access opening. The housing has cooperating internal components that operate to lock the door closed when the slide assembly is locked in place, to unlock the door when the slide assembly is released, to move the door open when the slide assembly is moved upwards, and to move the door closed when the slide assembly is moved downwards. Also, the frame assembly has adjustably positionable support elements for different firearms.