Steinheii is a mountain in the municipality of Bykle in Aust-Agder county, Norway. The tall mountain has a topographic prominence of which makes it the 10th highest mountain in Aust-Agder county. The mountain sits in the southwestern part of the municipality, just south of the lake Botsvatn and east of the lake Ytre Storevatnet. The nearest village is Bykle, located about to the northeast.