An optical sensing module for an electronic device is provided. The electronic device includes an opaque layer and an aperture formed on the opaque layer, wherein the optical sensing module includes an optical sensor; a light guide element, disposed between the opaque layer and the optical sensor and configured to guide light to the optical sensor through the aperture; and a diffusing layer, disposed between the opaque layer and the light guide element, configured to diffuse the light to the light guide element.