Moro Rebellion: United States Army troops bring overwhelming force against the native Moros in the First Battle of Bud Dajo, leaving only six survivors.

The First Battle of Bud Dajo, also known as the Moro Crater Massacre, was a counterinsurgency action fought by the United States Army against Moros in March 1906, during the Moro Rebellion in the southwestern Philippines. Whether the occupants of Bud Dajo were hostile to U.S. forces is disputed, as inhabitants of Jolo Island had previously used the crater, which they considered sacred, as a place of refuge during Spanish assaults. Major Hugh Scott, the District Governor of Sulu Province, where the incident occurred, recounted that those who fled to the crater "declared they had no intention of fighting, - ran up there only in fright, [and] had some crops planted and desired to cultivate them."The description of the engagement as a "battle" is disputed because of both the overwhelming firepower of the attackers and the lopsided casualties. The author Vic Hurley wrote, "By no stretch of the imagination could Bud Dajo be termed a 'battle'". Mark Twain commented, "In what way was it a battle? It has no resemblance to a battle ... We cleaned up our four days' work and made it complete by butchering these helpless people." A higher percentage of Moros were killed (99 percent) than in other incidents now considered massacres, such as the Wounded Knee Massacre. Some of those killed were women and children. Moro men in the crater who had arms possessed melee weapons. While fighting was limited to ground action on Jolo, use of naval gunfire contributed significantly to the overwhelming firepower brought to bear against the Moros.

During the engagement, 750 men and officers, under the command of Colonel J.W. Duncan, assaulted the volcanic crater of Bud Dajo (Tausg: Bd Dahu), which was populated by 800 to 1,000 Tausug villagers. According to Herman Hagedorn (who was writing prior to World War II), the position held by the Moros was "the strongest which hostiles in the Philippines have ever defended against American assault." Although the engagement was a victory for the American forces, it was also an unmitigated public-relations disaster. Whether a battle or massacre, it was certainly the bloodiest of any engagement of the Moro Rebellion, with only six of the hundreds of Moro surviving the bloodshed. Estimates of American casualties range from fifteen killed to twenty-one killed and seventy-five wounded.

The Moro Rebellion (1899–1913) was an armed conflict between the Moro people and the United States military during the Philippine–American War.

The word "Moro" – which is derived from the Spanish "Moor" – is a term for Muslim people who lived in the Southern Philippines, an area that includes Mindanao, Jolo and the neighboring Sulu Archipelago.