A pneumatic lockout device is disclosed. The device includes a first disc having a first slot and a first tab, and a second disc having a second slot and a second tab. The first disc is secured to the second disc. The device further includes a pneumatic fitting having a fitting groove positionable within the first slot and the second slot. The pneumatic lockout device is movable from an unlocked position to a locked position, while the fitting groove is positioned within the first slot and the second slot.