Gustaf Adolf Christensen Fjæstad (1868 - 1948) was a Swedish artist (painter, graphic artist, craftsman) and sportsman. He was married to the textile artist Maja Fjæstad.

Fjæstad, whose father was a shoemaker, studied at the Academy of Fine Arts in 1891-1892 and then for a time at the Artists' Association's school. In 1893 he was an assistant to Bruno Liljefors during his decoration work for the Biological Museum, and then had him and Carl Larsson as tutors in his artistic training.

In 1897 he had the opportunity to take over Christian Eriksson's old studio Oppstuhage in Taserud, from where he worked in the provincial romantic spirit that characterized his contemporaries and circle of friends.

He is known as the Master of the Rimfrost and founded the so-called Rackstadgruppen at Lake Racken near Arvika in Värmland, to which artists such as Björn Ahlgrensson, Bror Lindh and Fritz Lindström belonged. His painting is technically very skilled. His winter landscapes are well-known and are represented in museums such as the National Museum , the Gothenburg Museum of Art and the Thielska Gallery in Stockholm, the Kalmar Art Museum, the Rackstad Museum in Arvika and the Statens Museum for Kunst. Alongside his painting, he has also designed furniture, art forging and tapestries. Fjæstad belonged to the association Konstnärsförbundet.