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