George Allen Mansfield FRIBA (15 June 1834 – 20 January 1908) was a prominent Australian architect of the nineteenth century who designed many iconic buildings in Sydney, New South Wales, Australia.

Born in 1834 in Sydney, his father, the Reverend Ralph Mansfield, had been a Methodist missionary.

[1] He was educated at the privately run school of Mr. W. T. Cape and then articled with the architect John Frederick Hilly.

The family lived in Tranby, Glebe, which was designed by Mansfield.

[1][9] Mansfield was also the founder and first president of the NSW Institute of Architects (now the NSW Chapter of the Australian Institute of Architects).