Horatio Robert Forbes Brown (16 February 1854 – 19 August 1926) was a Scottish historian who specialised in the history of Venice and Italy.
Born in Nice, he grew up in Midlothian, Scotland, was educated in England at Clifton and Oxford, and spent most of his life in Venice, publishing several books about the city. He also wrote for the Cambridge Modern History, was the biographer of John Addington Symonds, and was a poet and alpinist.
Born at Nice (then part of the kingdom of Sardinia) on 16 February 1854, Brown was the son of Hugh Horatio Brown, an advocate, of New Hall House, Carlops, who was a Deputy Lieutenant for Midlothian, and of Gulielmina Forbes, the sixth daughter of Colonel Ranaldson MacDonnell of Glengarry and Clanranald (1773–1828). The marriage was in 1853, and his mother was a good deal younger than his father, who died on 17 October 1866, at the age of 66.
Brown's maternal grandfather, Ranaldson MacDonnell, of Invergarry Castle on Loch Oich in Inverness, Chief of Clan MacDonell of Glengarry, had been one of Walter Scott's closest friends.
His other grandfather was Robert Brown, Esq. (died 1834), of New Hall, Carlops, a large country house about twelve miles from the centre of Edinburgh, mostly dating from the 18th century but incorporating parts of a medieval castle. Enlargements to the house in 1785 were designed by Robert Brown, who later wrote a play called Mary's Bower and a book of Comic Poems in Scots. He was a lover of art, commissioning new work by Henry Raeburn, Andrew Geddes and John Watson Gordon.