Major General Johnson Thomas Umunnakwe Aguiyi-Ironsi (3 March 1924 – 29 July 1966) was a senior Nigerian military officer and second Nigerian Head of State. He seized power in the ensuing chaos following the January 15, 1966 military coup, serving as the Nigerian Head of State from 16 January 1966 until his murder on 29 July 1966 by a group of mutinous Northern army soldiers who revolted against his government in what was popularly called the July Counter Coup.