Hjalmar Welhaven (26 December 1850 – 18 April 1922) was a Norwegian architect, palace manager, and sportsman.

He was the son of writer Johan Sebastian Welhaven and Josephine Angelica Bidoluac.

Welhaven was a student at the Statens håndverks- og kunstindustriskole (now Norwegian National Academy of Craft and Art Industry) in 1870.

From 1905 he continued in this position for King Haakon VII of Norway, and led the comprehensive modernization project of the Royal Stables between 1905 and 1911, until he finally retired in 1920.

[3] Among his designs were the tourist cabins Glitterheim and Gjendebu, and Polhøgda, the home of Fridtjof and Eva Nansen.