An image reading apparatus includes an original tray, an original feeding portion, an original reading portion, an original discharging portion, an original discharge tray, an extension tray, and a rotation guide. A stacking surface of the original discharge tray is provided with an opening through which the rotation guide is capable of passing when the rotation guide rotates from a first position to a second position. In a state in which the extension tray is held at a pulled-out position, the rotation guide is rotatable relative to the extension tray from the first position toward the second position. In a state in which the extension tray is held at an accommodated position, the rotation guide is rotatable from the first position toward the second position by passing through the opening.