Hijiki (鹿尾菜 or 羊栖菜), or hijizkia, is a type of edible seaweed commonly found on rocky coastlines. Its scientific name is Hizikia fusiformis.

Hijiki has green to brown color when found in wild. After collected, it is boiled and dried to make dried hijiki to be sold. Dried processed hijiki turns black. It is soaked in water and cooked with ingredients like soy sauce and sugar to make a dish.