Eye tracking across multiple displays is supported with re-definition of a gaze vector matrix that correlates a surface of a first display with detected eye gazes as inputs to an information handling system to include a surface of a second display. Eye gazes that correlate to the second display are mapped to the redefined gaze vector matrix, such as with a calibration performed by a user or an estimate derived from tracked eye gazes. The information handling system applies a map of display surface areas to the gaze vector matrix to sort reported eye gazes as at a location of the first display surface, a location of the second display surface or discarded as outside of either display surface.