A ball valve comprising: a valve body with a seat for housing a ball provided with a coaxial through-opening and able to be rotationally operated from a closed valve position into an open valve position and vice versa; two opposite end flanges which are constrained to the valve body on opposite sides of the ball and provided with a respective, coaxial, internal hole and are suitable for connection to respective pipe sections; sealing means arranged between the valve body and the ball and comprising an annular member which is coaxial with the longitudinal axis (X-X) and carries an axial seal housed inside an associated axial seat inside which it is partially inserted in order to interfere with the outer surface of the ball, comprising a coaxial ring axially constrained to the annular seal-carrying member and interfering in the transverse direction (Y-Y) with a front surface portion of the seal in order to retain the latter in the axial direction.