Abstract: The window awning assembly includes an awning and an elongate roller tube for receiving the awning with the awning being rotatably disposed around the roller tube. An elongate awning case is provided which encloses the roller tube and awning, with the roller tube being mounted for rotation within the case. The case includes a main section which is adapted for mounting to a surface and a movable lead rail. The main section and the lead rail engage one another to totally enclose the roller tube and awning when the awning is rolled onto the roller tube. At least two spaced apart support arms are attached between the lead rail and a mounting surface and a coupling system is provided for enabling the support arms to be attached to the lead rail at various positions along the lead rail in order that the lead rail and awning can extend beyond the spacing of the support arms.