The 1999 Armenian parliament shooting, commonly known in Armenia as October 27 (Հոկտեմբերի 27, Hoktemberi k’sanyot’), was a terrorist  attack on the Armenian National Assembly in the capital of Yerevan on 27 October 1999 by a group of five armed men led by Nairi Hunanyan that, among others, killed the two de facto decision-makers in the country's political leadership—Prime Minister Vazgen Sargsyan and Parliament Speaker Karen Demirchyan. Their reform-minded coalition had won a majority in a parliamentary election held in May of that year and had practically sidelined President Robert Kocharyan from the political scene.

The shooting led to significant changes in the country's political landscape. It remains a subject of numerous conspiracy theories, mostly involving President Kocharyan, whose tenure thereafter was frequently criticized as authoritarian. Sargsyan and Demirchyan were posthumously honored with National Hero of Armenia titles.