Hilmar Örn Hilmarsson [ˈhɪlmar ˈœr̥tn̥ ˈhɪlmarsɔn] ( ), also known as HÖH (born 23 April 1958 in Reykjavík, Iceland), is a musician, an art director, and allsherjargoði (chief goði) of Ásatrúarfélagið ("the Ásatrú Association").

Hilmar Örn Hilmarsson was a pioneer in the use of computers when composing music and cleared the path for new ideas in recording and arrangements. He has worked on ambitious, experimental and original projects with various musicians, such as Psychic TV, Current 93, Sigur Rós, Steindór Andersen and Eivør Pálsdóttir.