A sheet tray assembly including: (a) a tray unit configured to accommodate sheets, and having an upper opening for allowing the sheets to be introduced into the tray unit via the upper opening; (b) a cover unit configured to cover the upper opening; and (c) a link interconnecting the tray unit and the cover unit, and having (c-1) a first end portion at which the link is connected to the tray unit and (c-2) a second end portion at which the link is connected to a proximal end portion of the cover unit. The link is movable between first and second pivot positions as a result of pivot movement of the link relative to the tray unit, whereby a posture of the link is changeable by the pivot movement, such that the second end portion of the link is placed in a first height level when the link is positioned in the first pivot position, and is placed in a second height level that is higher than the first height level when the link is positioned in the second pivot position.