List of state leaders in 340

This is a list of heads of state, government leaders, and other rulers in the year 340.

Africa

• Axum – Ezana, King of Axum (c.330-c.356)

Asia

• China (Sixteen Kingdoms Period)
  • Eastern Jin Dynasty - Emperor Cheng, Emperor of China (325–342)
  • Later Zhao - Shi Hu, Emperor of Later Zhao (334-349)
  • Cheng Han - Li Shou, Emperor of Cheng Han (338-343)
  • Former Liang - Zhang Jun, Emperor of Former Liang (324-346)
  • Former Yan - Murong Huang, Prince of Yan (337-348)
  • Tuyuhun Kingdom – Mùróng Yèyán (329–351)
• Japan - Emperor Nintoku (313–399)
• Korea (Three Kingdoms Period)
  • Baekje - Biryu, King of Baekje (304–344)
  • Goguryeo - Gogugwon, King of Goguryeo (331–371)
  • Silla - Heulhae, King of Silla (310–356)
• Kushan Empire – Shaka I, Emperor of the Kushans (c.325–345)
• India (Gupta Empire) – Samudragupta (335–380)
• Pallava - Simha Varman I, King of Pallava (315–345)

Europe

• Roman Empire
  • Constantine II, Roman Emperor in Gaul (337–340)
  • Constans, Roman Emperor in Illyria, Italy and Africa (337–350)

Middle East

• Roman Empire
  • Constantius II, Roman Emperor in the Orient (337–361)
• Sassanid Empire
  • Shapur II (310–379)
• Caucasian Iberia
  • Mirian III of Iberia (318–360)
• Armenia
  • Tigranes VII (Tiran), King of Armenia (339-c.350)