Denis J. Halliday is an Irish diplomat. He was the United Nations Humanitarian Coordinator in Iraq from 1 September 1997 until 1998, and earlier the Deputy Resident Representative to Singapore of the United Nations Development Programme.

On 6 August 1990, four days after the Iraqi invasion of Kuwait, the United Nations Security Council (UNSC) placed a comprehensive embargo on Iraq. The sanctions stayed largely in force until 22 May 2003, and persisted in part, including reparations to Kuwait. The original stated purposes of the sanctions were to compel Iraq to withdraw from Kuwait, to pay reparations, and to disclose and eliminate any weapons of mass destruction (WMD).