Sir (Robert) Arthur Arnold (28 May 1833 – 20 May 1902) was a Liberal Party politician and author. Educated privately and trained as a surveyor and land agent, in 1861 he was involved in the surveying operations prior to the construction of the Thames Embankment. In 1867 he married Amelia Elizabeth Hyde of County Cork. They had no children. His wife was a campaigner for women's suffrage and a prominent public figure in her own right. From 1880-85 he was member of parliament for Salford, Lancashire. He died at his home in Kensington in May 1902, aged 68.