Otto Valstad (11 December 1862 – 20 June 1950) was a Norwegian painter, book illustrator and children's writer. He was born in Asker, and was married to Tilla Valstad. Their home in Hvalstad was a cultural centre, and has later been made into a museum, a part of Asker Museum. Among his books are Juletræet from 1891, Smaakarer from 1910, Ola Enfoldig from 1916 and Ola Mangfoldig from 1923. He is represented in the National Gallery of Norway with the portrait Fru Lina Brun from 1901.