Richard Southwell Bourke, 6th Earl of Mayo, (English: ; BURK; 21 February 1822 – 8 February 1872) styled Lord Naas (; NAYSS) from 1842 to 1867, was a prominent British statesman, colonial administrator, and diplomat. He was a Member of Parliament from the British Conservative Party from 1847 to 1868, and served as the Chief Secretary for Ireland for three terms (1852, 1858–9, 1866–8). In 1869, he was appointed as the 4th Viceroy of India with the political title Lord Mayo. During an official visit to Port Blair in 1872, he was assassinated and was the only Viceroy of India to be killed while in office.