A customizable alignment sighting device for a golf club is mounted to an upper surface of the head of the golf club with a sighting element providing the user a visual target indicator for desired alignment of the club head with the user's line of sight. The sighting element can be readily adjusted for the user's preferences. When not aligned, the sighting element provides an indication of the magnitude and direction of misalignment. In one embodiment, the device is shaped as a planar disc mounted on the upper surface of the club head by leveling posts spaced around its periphery. The sighting element is a concave lens or lenticulated grid or grill superimposed on a target image. In another embodiment, the device has a 3D device body mounted in a mounting cup or socket fastened to or formed in the head of the golf club. The device body has a larger-diameter circle marked around an annular opening, and a smaller-diameter circle marked depthwise inside the opening in the device body to provide a target of concentric circles by parallax effect. The device body can be formed as a sphere with axially split sides that are expanded outward when an expansion plug is threaded in the bottom, providing an interference fit holding it in position in the mounting cup. The spherical body can be formed with 4 alignment sighting holes at 90.degree. intervals around a vertical plane and provided with a weighting element fixed at an offset position, such that it can be rotated to use any of the different alignment holes for adjusting the weight distribution in the club head.