Hovhannes Kajaznuni or Katchaznouni was an Armenian architect and politician who served as the first prime minister of the First Republic of Armenia from 6 June 1918 to 7 August 1919. He was a member of the Armenian Revolutionary Federation.

The prime minister of Armenia is the head of government and most senior minister within the Armenian government, and is required by the constitution to "determine the main directions of policy of the Government, manage the activities of the Government and coordinate the work of the members of the Government." Also, according to the constitution, the prime minister heads the Security Council, which prescribes the main directions of the country's defense policy; thus, the prime minister is effectively the commander-in-chief of the Armed Forces of Armenia. Nikol Pashinyan is the current prime minister. He took the office on 8 May 2018 following the resignation of Serzh Sargsyan.