FUJIWARA no Kogikoso (year of birth and death unknown), written as "藤原古木古曾" or "藤原古木古曾," was a noble female during the Heian period who was the wife of FUJIWARA no Sukemichi.
藤原小忌古曾（ふじわらのこぎこそ、生没年不詳）または藤原古木古曾は、平安時代の女性貴族で藤原相通の妻にあたる。