Abstract: A portable door lock has a relatively-thin sheet-metal locking strap that fits between the door and the jamb. The strap has a fixed bolt on one end that is received in the recessed keeper in the jamb, with the door in the open position. The door is closed over the strap; and a locking dog pivotably mounted on the other end of the strap, is pivoted towards the door such that the dog partially overlaps the strap, and such that the outer face of the dog engages the inner side of the door, thereby preventing the door from being opened from the outside. The outer face of the dog may be arcuately formed to accommodate different door thicknesses within a given range, and the outer arcuate face may have a frictional layer for non-slip purposes and to prevent any marring of the door finish. A retainer may be provided over the dog and the strap to retain the portable door lock in its locking position.