The Hanthawaddy Kingdom (also Hanthawaddy Pegu or simply Pegu) is the dominant kingdom that rules lower Burma (Myanmar) from 1287 to 1539 and from 1550 to 1552.

The Mon-speaking kingdom is founded as Ramannadesa and Mon by King Wareru following the collapse of the Pagan Empire in 1287 as a nominal vassal state of Sukhothai Kingdom, and of the Mongol Yuan dynasty.

The kingdom becomes formally independent of Sukhothai in 1330 but remains a loose federation of three major regional power centers: the Irrawaddy delta, Pegu, and Martaban.

Its kings have little or no authority over the vassals.

Martaban is in open rebellion from 1363 to 1388.