The Toungoo–Hanthawaddy War (1534–1541) () was a military conflict between Toungoo Kingdom, and the Hanthawaddy Kingdom and its allies the Prome Kingdom and the Confederation of Shan States that took place in present-day Lower Burma (Myanmar) between 1534 and 1541. In a series of improbable events, the upstart Burmese-speaking kingdom defeated Mon-speaking Hanthawaddy, the most prosperous and powerful of all post-Pagan kingdoms before the war. In the following years, Toungoo used the newly acquired kingdom's wealth and manpower to reunify the various petty states that had existed since the fall of Pagan Empire in 1287.