If you find your eyeliner is streaking midday or eyeshadow has trouble staying put, you may have oily eyelids. A few things may cause this to happen: (1) You may just have oily skin. (2) You have overactive meibomian glands—those tiny oil glands that line the edges of your upper and lower eyelids. They produce oil to coat the eye, but when they make too much, it causes oily eyelids. (3) Your skincare products may be stripping your skin dry of natural oils. When that happens, your skin produces more oil to compensate for the loss.