Robert Hamilton Lloyd-Anstruther (21 April 1841 – 24 August 1914) was a British army officer and Conservative Party politician.^[1][2]

The son of Captain James Hamilton Lloyd-Anstruther and his wife Georgiana née Burrell.^[1] Following officer training at the Royal Military College, Sandhurst, he entered the Rifle Brigade as an ensign in 1858,^[3] and immediately saw action in the later stages of the Indian Mutiny.^[2] In 1862 he rose to the rank of lieutenant by purchase^[4] He fought in the operations to repulse the Fenian raids in Canada in 1866, and was promoted to captain in 1872.^[5] In 1871 he married Gertrude Louisa Georgiana Fitzroy of Hampshire. He served as a garrison instructor for the South Eastern District until 1881 when he was appointed aide de camp to General Edward Newdegate in the Colony of Natal in 1881.^[6] He retired on half pay in the same year.^[7] However, he returned to the army shortly afterwards, rising to the rank of major and serving with distinction in the Suakin Expedition of 1885.^[2] In that year he retired from the army with the rank of honorary lieutenant-colonel in the Suffolk Rifle Volunteer Corps.^[2]

At the 1886 general election, Lloyd-Anstruther was chosen by the Conservative Party to contest the South Eastern or Woodbridge Division of Suffolk, a constituency held by the Liberal Party Member of Parliament, Robert Lacey Everett.^[8] He won the seat for the Conservatives, but only served a single term in parliament, with Everett regaining the seat in 1892 general election.^[2][8]

On his father's death in 1882, Lloyd-Anstruther had inherited Hintlesham Hall near Ipswich in Suffolk.^[9] He later entered local government as an alderman on East Suffolk County Council, and was appointed a justice of the peace and a deputy lieutenant of Suffolk.^[1][2] He died in 1914,^[10] survived by his wife and one son, Fitzroy Anstruther-Gough-Calthorpe, who was later created a baronet.^[1]