A screen assembly for a vibratory separator includes a composite screen frame that has a rigid support section formed from a polymer material and a cushioned strain relief zone. The strain relief zone is located along the inner periphery of the rigid support section and provides support at the interface between the screen frame and the screen cloth. The strain relief zone may extend along an inner peripheral wall of the rigid support section. The rigid support section may include a flange and the strain relief zone may extend around the rigid support section to encapsulate the flange in addition to providing additional support to the screen cloth. The rigid support section and the strain relief zone may be co-formed in a molding process. Alternatively the rigid support section may be a molded member and the strain relief zone may be an extrusion to be assembled to the rigid support member. The screen cloth is affixed to the peripheral frame. The screen frame may include an internal support frame having a rigid support section defining a plurality of openings, each of which has a strain relief zone around its periphery to provide cushioned support to the screen cloth across the opening.