Abstract: An adjustable frame assembly for a door, window or other opening in a building utilizes sets of first and second brackets to secure a frame component along a side of the opening in a manner which allows for easy adjustment in the width and depth of the mounted members. The first bracket is formed with a first flange portion extending outside the opening and a second flange portion projecting inside the opening, while the second bracket extends from the frame component. The second flange portion of the first bracket is adjustably secured to the frame component through the second bracket, potential with an interposed, varying width accommodating spacer member, such that the first frame component is secured to the wall stud through the first and second brackets with a distance between a facer portion of the first frame component and the first flange portion being adjustable.