The Konbaung–Hanthawaddy War (Burmese: ကုန်းဘောင်-ဟံသာဝတီ စစ်) was the war fought between the Konbaung Dynasty and the Restored Hanthawaddy Kingdom of Burma (Myanmar) from 1752 to 1757. The war was the last of several wars between the Burmese-speaking north and the Mon-speaking south that ended the Mon people's centuries-long dominance of the south.The war began in April 1752 as independent resistance movements against Hanthawaddy armies which had just toppled the Toungoo Dynasty. Alaungpaya, who founded the Konbaung Dynasty, quickly emerged as the main resistance leader, and by taking advantage of Hanthawaddy's low troop levels, went on to conquer all of Upper Burma by the end of 1753. Hanthawaddy belatedly launched a full invasion in 1754 but it faltered. The war increasingly turned ethnic in character between the Burman (Bamar) north and the Mon south. Konbaung forces invaded Lower Burma in January 1755, capturing the Irrawaddy Delta and Dagon (Yangon) by May. The French defended port city of Syriam (Thanlyin) held out for another 14 months but eventually fell in July 1756, ending French involvement in the war. The fall of the 16-year-old southern kingdom soon followed in May 1757 when its capital Pegu (Bago) was sacked. Disorganized Mon resistance fell back to the Tenasserim peninsula (present-day Mon State and Tanintharyi Region) in the next few years with Siamese help but was driven out by 1765 when Konbaung armies captured the peninsula from the Siamese.

The war proved decisive. Ethnic Burman families from the north began settling in the delta after the war. By the early 19th century, assimilation and intermarriage had reduced the Mon population to a small minority.