Sir Robert Lucas Lucas-Tooth, 1st Baronet (7 December 1844 – 19 February 1915) was an Australian politician. He was born in Sydney, the son of Edwin Tooth and Sarah Lucas, and was educated at Eton College. He returned to Australia in 1863, joining the family firm and becoming involved in the brewery business. He owned land near Bega. On 2 January 1873 he married Helen Tooth, his first cousin who was a daughter of Frederick Tooth; they had six children. From 1875 he had built an impressive mansion on Sydney harbour suburb called Swifts, Darling Point which was designed in the Gothic revival style. From 1880 to 1884 he represented Monaro in the New South Wales Legislative Assembly.