The Battle of Slater's Knoll (28 March – 6 April 1945) was a battle fought between Australian and Japanese forces on Bougainville Island during the Second World War. Part of the Bougainville campaign, the battle occurred as a force of about 3,300 Japanese from the Japanese 6th Division, including artillery and other supporting elements, launched a counterattack against the main Australian offensive which had been pushing south towards Buin, concentrating their attacks on Slater's Knoll near the Puriata River. The Australian troops belonged to the 7th Brigade, with the 25th Infantry Battalion being the most heavily engaged, although the 9th Infantry Battalion and the 61st Infantry Battalion also took part in the fighting.

Against Japanese tactics that included massed attacks, the Australians utilised armour and artillery, and in the end these proved decisive. Commencing in late March, after the Australian advance had been halted by wet weather, over the course of several days the Japanese launched several probing raids followed by heavy attacks against the Australians. The final assault on the knoll came on the night of 4/5 April when 129 men from 'B' Company, 25th Infantry Battalion repulsed an attack by a force of about 1,100 Japanese, killing 292. This proved to be the 7th Brigade's final involvement in the campaign as they were relieved by the 15th Brigade shortly afterwards. Overall, 620 Japanese were killed in the battle with another 1,000 estimated to have been wounded, while the Australians suffered 189 casualties.