Abstract: A bracket for mounting an air conditioning unit in a window has a base plate having a front edge and a rear edge and a pair of support legs connected to the base plate and extending from the rear edge, each support leg having an end face that faces in a same direction as the front edge and a support trough connected to the front edge. There are adjustable arms connected to the support trough. These arms are slidable in opposite directions to increase the width of the bracket and fit it exactly to the width of the window frame. When the bracket is positioned in a window frame of a structure, the support trough fits within the window frame and the end faces of the each support leg rest against an exterior of the structure.