Ingvi Sigurður Ingvarsson (12 December 1924 – 26 September 2009) was an Icelandic diplomat.
Ingvi worked for the tax office and the Embassy of the United States in Reykjavík.
From 1971 to 1972 he was Deputy Secretary General of the Ministry for Foreign Affairs (Iceland) in Reykjavík.
From 1972 to 1976 he was Permanent Representative next the Headquarters of the United Nations in New York City.
From 24 November 1986 to 17 December 1990 he was ambassador in Washington, D. C. From 28 April 1987 to 24 January 1991 he was coaccreditated in Ottawa.