Ka, also Sekhem Ka, was a predynastic pharaoh of Upper Egypt. He ruled over Abydos in the late 32nd or early 31st century BC and was buried at Umm el-Qa'ab. He most likely was the immediate successor to Iry-Hor and was succeeded by Narmer. He is the earliest known Egyptian king with a "serekh," inscribed on a number of artefacts.