The Tulsa race massacre took place on May 31 and June 1, 1921, when mobs of White residents, some of whom had been deputized and given weapons by city officials, attacked Black residents and destroyed homes and businesses of the Greenwood District in Tulsa, Oklahoma, US. Alternatively known as the Tulsa race riot or the Black Wall Street massacre, the event is considered one of "the single worst incident[s] of racial violence in American history", and is believed to be one of the deadliest terrorist attacks in the history of the United States. The attackers burned and destroyed more than 35 square blocks of the neighborhood – at the time one of the wealthiest Black communities in the United States, known as "Black Wall Street".More than 800 people were admitted to hospitals, and as many as 6,000 Black residents of Tulsa were interned in large facilities, many of them for several days. The Oklahoma Bureau of Vital Statistics officially recorded 36 dead. A 2001 state commission examination of events was able to confirm 39 dead, 26 Black and 13 White, based on contemporary autopsy reports, death certificates, and other records. The commission gave several estimates ranging from 75 to 300 dead.The massacre began during the Memorial Day weekend after 19-year-old Dick Rowland, a Black shoeshiner, was accused of assaulting Sarah Page, the 17-year-old white elevator operator in the nearby Drexel Building. He was taken into custody. After Rowland was arrested, rumors that stated that he was going to be lynched were spread throughout the city, which had seen a White man named Roy Belton lynched the previous year. Upon hearing reports that a mob of hundreds of White men had gathered around the jail where Rowland was being held, a group of 75 Black men, some of whom were armed, arrived at the jail in order to ensure that Rowland would not be lynched. The sheriff persuaded the group to leave the jail, assuring them that he had the situation under control.

The most widely-reported and corroborated inciting incident occurred as the group of Black men left, when an elderly White man approached O.B. Mann, a Black man, and demanded that he hand over his pistol. Mann refused, and the old man attempted to disarm him. Mann shot him, and then, according to the sheriff's reports, "all hell broke loose." At the end of the exchange of gunfire, 12 people were dead, 10 White and two Black. Subsequently the militants reportedly fled back into Greenwood, shooting as they went. Alternatively, another eyewitness account contends that the shooting began "down the street from the Courthouse" when Black business-owners came to the defense of a lone Black man being attacked by a group of around six White men. Although it's possible the eyewitness simply didn't recognize this incident as being part of a rolling gunfight already underway. In either case, as news of the violence spread throughout the city, mob violence exploded. White rioters invaded Greenwood that night and the next morning, killing men and burning and looting stores and homes. Around noon on June 1, the Oklahoma National Guard imposed martial law, ending the massacre.

About 10,000 Black people were left homeless, and property damage amounted to more than $1.5 million in real estate and $750,000 in personal property (equivalent to $32.65 million in 2020). Many survivors left Tulsa, while Black and White residents who stayed in the city largely kept silent about the terror, violence, and resulting losses for decades. The massacre was largely omitted from local, state, and national histories.

In 1996, 75 years after the massacre, a bipartisan group in the state legislature authorized the formation of the Oklahoma Commission to Study the Tulsa Race Riot of 1921. The commission's final report, published in 2001, states that the city had conspired with the mob of white citizens against Black citizens; it recommended a program of reparations to survivors and their descendants. The state passed legislation to establish scholarships for the descendants of survivors, encourage the economic development of Greenwood, and develop a park in memory of the victims of the massacre in Tulsa. The park was dedicated in 2010. Schools in Oklahoma have been required to teach students about the massacre since 2002, but in 2020, the massacre officially became a part of the Oklahoma school curriculum.