Abstract: A pet ventilation panel for a vehicle window opening is disclosed. The vehicle window opening is typically defined by a retractable windowpane movable within a window frame having upper, lower and opposed side frame members. The ventilation panel includes a selectively removable window insert formed from a single sheet of material. The insert has an upper edge adapted for engagement with an upper frame member of a vehicle window frame, and side edges adapted for engagement with side frame members of the vehicle window frame to cover at least a portion of the vehicle window opening. A central opening is defined by a continuous edge in the insert. The opening is sized and shaped to permit penetration thereof by the head of an animal disposed within the vehicle without permitting passage of the animal's body therethrough to prevent inadvertent escape from the vehicle by the animal. A mechanism is provided for maintaining the insert in position within the vehicle window opening.