Generally, an end effector assembly for a substrate transfer robot is provided. In one embodiment, an end effector assembly for supporting a quadrilateral substrate during substrate transfer includes an end effector having an inner edge support disposed on a first end and a first outer edge support disposed on a distal end. The first end of the end effector is adapted for coupling to a robot linkage. The first inner edge support has a face that is oriented parallel to and facing the face of the first outer edge support. This configuration of edge supports captures the substrate to the end effector thereby minimizing substrate slippage during transfer. In another embodiment, lateral guides may be utilized to further enhance capturing the substrate along the edges of the substrate open between the inner and outer edge supports.