Hassa Horn Sr. (16 March 1837 – 11 December 1921) was a Norwegian civil servant.
He was born in Frederiksvern of customs inspector Hans Jokum Horn and Anna Grønbech Aas.
[2] Their daughter Dorothea was the mother of national housewives' leader Alette Nicolaysen.
In 1886 reached the pinnacle of his career as he was appointed as chief administrative officer of the third magistrate department in Kristiania Municipality, the capital city of Norway.
[1][4] He was the capital's highest-ranking civil servant responsible for education, libraries and church affairs.