A handgun has a reliable, integrated, lockable safety/hammer lock which is easy to operate and inexpensive to manufacture. The handgun contains a frame having shaft receiving recesses, a hammer supported in the frame, and a lockable safety/hammer lock disposed in a slidable fashion in the frame. The safety/hammer lock has a locking shaft for engaging in the shaft receiving recesses and a hammer locking rail for preventing the hammer from actuating or cocking.