Hieronymus Heyerdahl (5 May 1867 – 13 January 1959) was a Norwegian lawyer, administrator and politician for the Conservative Party.

His parents were Hieronymus Heyerdahl (1832–1876) and Henriette Sophie Schou (1839-1929).

He was the grandson of Hieronymus Heyerdahl (1773–1847) who had served at the Norwegian Constituent Assembly in 1814.

He entered the law school at Gjertsens skole in 1884 and earned his cand.jur.

Heyerdahl launched the fundraising campaign for a new Oslo City Hall in 1914.