Frederick William Hagelthorn (23 January 1864 – 21 July 1943) was an Australian politician.
He was born near Ballarat to Swedish-born seaman Frederick Hagelthorn and Mary Robertson.
He established a store at Portland and then Horsham, where he then changed careers to become a stock and station agent in 1904.
Hagelthorn left the front bench in 1917, and in 1919 attempted to transfer to South Eastern Province without success.
After leaving the parliament, Hagelthorn worked as an estate agent in Melbourne, with some success.