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 .
- Michael Rice, Who's Who in Ancient Egypt, Routledge 1999, p.86
- Ian Shaw, The Oxford History of Ancient Egypt, p.71
- Toby A. H. Wilkinson, Early Dynastic Egypt, Routledge 1999, pp.57f.