Sir Fitzroy Hamilton Niall Anstruther-Gough-Calthorpe, 1st Baronet (5 July 1872 – 29 September 1957), born FitzRoy Hamilton Niall Lloyd-Anstruther, was an English baronet.
He was the son of Robert Hamilton Lloyd-Anstruther (1841–1914), by his marriage on 5 July 1871 to Gertrude Louisa Georgina FitzRoy (1850–1923), a daughter of Francis Horatio FitzRoy (1823–1900), by his marriage in 1849 to the Hon. Gertrude Duncombe (1827–1916). His paternal grandparents were James Hamilton Lloyd-Anstruther (1806–1882) and Georgiana Charlotte Burrell (1811–1843), who had been married in 1838.
He had a brother, Reginald Lloyd-Anstruther, who died as a child in 1875, and a sister, Rosalind Gertrude (died 1903), the wife of Brigadier General Noel Armar Lowry-Corry (1867–1935), by whom she had issue.
On 7 November 1910 he changed his surname name from Lloyd-Anstruther to Anstruther-Gough-Calthorpe, discarding the name of Lloyd and adding his wife's surnames. Before the First World War he served as a part-time Lieutenant in the Army Motor Reserve, then in September 1915 was appointed as an ADC on the General Staff, ending the war with the rank of Captain. He was created a Baronet on 1 July 1929.
On 11 October 1898, FitzRoy Lloyd-Anstruther (as he then was) married the Hon. Rachel Gough-Calthorpe (1871-1951), a daughter of Augustus Gough-Calthorpe, 6th Baron Calthorpe, and Maud Augusta Louisa Duncombe. They had issue: