Henry Francis Seymour Moore, 3rd Marquess of Drogheda KP PC (I) (14 August 1825 – 29 June 1892) was an Irish peer, styled Viscount Moore until 1837. He became Marquess of Drogheda in 1837 on the death of his uncle Charles Moore, 2nd Marquess of Drogheda and was appointed a Knight of the Order of St Patrick on 7 February 1868. He served as Lord Lieutenant of Kildare from 1874 until his death.
His uncle Charles had been insane for many years, but there is no evidence that Henry was similarly afflicted. He had no children and on his death the Marquessate became extinct; the title Earl of Drogheda passed to a cousin, Ponsonby Moore.