Abstract: An awning window frame is disclosed which defines a supporting shelf positioned to support a rigid glazing pane, such as glass. The frame defines a ridge extending over the support surface in a spaced relationship thereto, and this ridge is shaped and configured to retain a beading strip. The beading strip fits between the ridge and the supporting shelf in order to conceal the junction between rigid glazing pane and the shelf. When it is desired to use the window frame with a flexible glazing sheet, such as a plastic sheet, the beading and pane are removed and the sheet is held in place on the window frame by means of a channel and spline arrangement. In some preferred embodiments, the channel is defined in the supporting shelf such that the window frame serves to support both the flexible glazing sheet and the rigid glazing pane in the same plane.