Abstract: A ball joint for a stabilizer includes a metal stud ball having a spherical head and a pillow ball seat for swingably supporting the metal stud ball. The pillow ball seat includes a plastic cylindrical seat member, a top wall portion integral with the top of the seat member, a metal cylindrical piece member fitted on the seat member, a plastic disklike cap member fitted on the top wall portion of the seat member, and means for securing the cap member to the top wall portion of the seat member. The seat member has an annular spherical concave surface formed in the inner periphery thereof. The spherical head of the stud ball is pressure-fitted in the seat member and swingably supported on the concave surface.