Trollsteineggi or Trollsteineggje is a mountain in Lom Municipality in Innlandet county, Norway. The 2300 m tall mountain is the 22nd tallest mountain in Norway. It is located in the Jotunheimen mountains within Jotunheimen National Park. The mountain sits about 20 km south of the village of Fossbergom and about 14 km southeast of the village of Elvesæter. The mountain is surrounded by several other notable mountains including Trollsteinrundhøe to the north, Grotbreahesten to the northeast, and Glittertinden to the south. The population density of the area around Trollseteinseggi is less than 2 PD/km2. The area around Trollsteineggi is almost completely covered with grass. The climate is boreal.