Stein Arve Ytterdahl (born 4 October 1951) is a Norwegian politician and public servant. He served as the County Governor of Agder county from 2016 until 2022. Ytterdahl was born in Namsos in 1951 and he received a degree in civil engineering in 1975 from the Norwegian University of Science and Technology in Trondheim. During his career, he worked in various management positions at Norsk Hydro in Porsgrunn and then Karmøy, at Elkem at the Lista Smeltverk and then as the CEO of Sauda Smelteverk. He also worked for Statoil, , and Boliden AB in Odda. He also spent two years as the director of higher education at the BI Norwegian Business School.