An intake air control apparatus for a vehicle may include a valve flap provided in an air intake passage, the valve flap having a rotation shaft facing opposite sides of the air intake passage, to control a cross-sectional area of air intake flow according to a rotation angle thereof about the rotation shaft; a driving device supplying a driving force to the valve flap; and a port plate being provided in the air intake passage, with a longitudinal direction thereof being in parallel to a longitudinal direction of the air intake passage, the port plate dividing the air intake passage into an upper passage and a lower passage, wherein based on a width direction, at least a portion of the port plate has a height changing portion that changes a height of the port plate from a lower internal wall of the air intake passage.