There is disclosed a removable vent window for a roof of an automobile which is particularly adapted for retrofit installation. The vent window is mounted in an opening extending across a major width of a car roof, preferably slightly rearwardly of the forward edge of the roof. The opening is framed with members of preformed or stretch formed extruded aluminum which are stretch formed into a generally rectangular frame to provide support for the hinges and latches that secure the vent window. The vent window is removably mounted in the opening by hinge members along the forward edge of the opening. The rear edge of the opening and window bear detachable latching mechanisms whereby the window can be pivoted between a closed, sealing position and an open, forwardly inclined, venting position. The latch mechanisms can be detached from the window, freeing the rear edge of the window and permitting it to be pivoted to an elevated position and disengaged from its hinges for complete removal of the window. The window is installed in existing roof panels by cutting the panel to the approximate dimensions of the desired opening, placing the preformed frame members into the opening and applying a bonding adhesive between the frame members and the panel surrounding the opening. The vent window is shaped with a surface contour that approximates the contour of the roof and the panel is mounted in the frame members and latched into its closed position so that the frame members and surrounding roof are clamped into the desired roof contour by the rigid window panel. The assembly is retained in this clamped configuration until the bonding adhesive has cured sufficiently that the frame members support the surrounding roof panel.