A sealing device for a wheel hub assembly connected to a constant velocity joint and intended to be interposed between an inner ring and an outer ring of the wheel hub assembly and to extend straddling between the wheel hub and the constant velocity joint; the sealing device comprising a first annular shield, stationary in use, and a second annular shield, rotating in use, which are adapted to be anchored by means of respective annular journalling sleeve-shaped portions (17, 22) thereof to the outer ring and to the inner ring of the wheel hub assembly, respectively, and having each a respective annular flange portion (18, 23) which radially extends in cantilever fashion from the journalling portion and toward the other shield, and an annular sealing element carried by the first shield and which is provided with a plurality of annular sealing lips (25, 26, 27); the flange portion of the second shield carrying, on the side opposite to the first shield and in use toward the constant velocity joint, an annular signal generating element made of a synthetic plastic or magnetizable elastomeric wherein the flange portion of the second shield comprises a first radially outer annular stretch opposite to the journalling portion of the second shield, and which extends axially from the same side of the annular journalling portion of the second shield and toward the first shield; wherein a first radially outer annular lip of the annular sealing element radially and axially extending in cantilever fashion from the first shield and toward the second shield so as to move obliquely away from the symmetry axis, and being arranged radially on the inside of the first annular stretch of the flange portion of the second shield; and wherein a free end of the first annular lip forming, with a radially inner end of the first annular stretch and within an annular chamber delimited between the first and the second shields, a labyrinth seal, which is directed axially; characterized in that, in combination, i)- the annular journalling portion of the first shield is intended to fluid-tightly couple, in use, radially on the outside of the outer ring of the wheel hub assembly; the first annular stretch of the flange portion is incurved radially from the exterior toward the interior and on the side opposite to the first shield to form in radial section a U arranged parallel to a common symmetry axis of the first and the second annular shields and having a concavity thereof facing the side opposite to the first shield to form a curved bottom annular channel on the side of the signal generating element; iii)- an end edge of the first annular stretch of the flange portion of the second shield being arranged on the side opposite to, and radially flush with, the annular journalling portion of the shield; iv)- a curved bottom wall of the annular channel formed by the first annular stretch of the flange portion of the second shield cooperating without contact with the flange portion of the first shield to form therewith, in a radial position which is more inner than the radial position of the annular journalling portion of the first shield, a first labyrinth seal, which is directed radially; v)- the first radially outer annular lip forms a V-shaped annular channel facing radially toward the exterior and arranged in radial section immediately below the first annular stretch of the flange portion of the second shield. i)- the annular journalling portion of the first shield is intended to fluid-tightly couple, in use, radially on the outside of the outer ring of the wheel hub assembly; the first annular stretch of the flange portion is incurved radially from the exterior toward the interior and on the side opposite to the first shield to form in radial section a U arranged parallel to a common symmetry axis of the first and the second annular shields and having a concavity thereof facing the side opposite to the first shield to form a curved bottom annular channel on the side of the signal generating element; iii)- an end edge of the first annular stretch of the flange portion of the second shield being arranged on the side opposite to, and radially flush with, the annular journalling portion of the shield; iv)- a curved bottom wall of the annular channel formed by the first annular stretch of the flange portion of the second shield cooperating without contact with the flange portion of the first shield to form therewith, in a radial position which is more inner than the radial position of the annular journalling portion of the first shield, a first labyrinth seal, which is directed radially; v)- the first radially outer annular lip forms a V-shaped annular channel facing radially toward the exterior and arranged in radial section immediately below the first annular stretch of the flange portion of the second shield.