An elongate strap to be used to hold a trash bag in a vehicle has a specially-shaped head rest post catch portion at one end and a specially-shaped bag handle hook portion at the other. The catch portion is placed to partially encircle both head rest posts on a vehicle seat, allowing the strap to drape over the shoulder of the seat so that the hook portion hangs between the seats. The hook portion comprises two spaced-apart funnel shaped cuts which hold the handles of a plastic grocery bag apart for easy disposal of trash by either left or right seat occupant.