A stacked-die image sensor may be provided with an array of image pixels. The stacked-die image sensor may include at least first and second integrated circuit dies stacked on top of one another. Some of the pixel circuitry in each pixel may be formed in the first integrated circuit die and some of the pixel circuitry in each pixel may be formed in the second integrated circuit die. Coupling structures such as conductive pads may electrically couple the pixel circuitry in the first integrated circuit die to the pixel circuitry in the second integrated circuit die. A shielding structure may partially or completely surround each conductive pad to reduce parasitic capacitive coupling between adjacent conductive pads. The shielding structure may be a metal wire coupled to a ground voltage. The shielding structure may extend between columns of image pixels and/or between rows of image pixels.