Abstract: A portable door lock (10) which is releasably coupled to door frame (12) and a door member (14) for positionally constraining the door member (14) to the door frame (12) when the portable door lock (10) is in an operational mode. The portable door lock (10) includes a door engagement mechanism (16) which is insertable between the door member (14) and the door frame (12) at the interface thereof. The door engagement mechanism (16) matingly engages the door member (14) on front and rear surfaces (20 and 22) and contacts the door frame (12) on a rear surface (24). A locking bar mechanism (62) is longitudinally displaceable on the door engagement mechanism (16) and extends across the interface (18) of the door member (14) and the door frame (12) for contacting the frontal surfaces (20 and 64) of the door frame (12) and the door member (14).