Herbert Rowse Armstrong TD. MA. (13 May 1869 – 31 May 1922) was an English solicitor and convicted murderer, the only solicitor in the history of the United Kingdom to have been hanged for murder. He was living in Cusop Dingle, Herefordshire, England and practising in Hay-on-Wye, on the border of England and Wales, from 1906 until his arrest on 31 December 1921 for the attempted murder of a professional rival by arsenic poisoning. He was later also charged and tried for the murder of his wife.