Black Lives Matter (BLM) is a decentralized political and social movement that aims to highlight racism, discrimination and racial inequality experienced by Black people in the United States, and to promote anti-racism. Its primary concerns are police brutality and racially motivated violence against Black people. The movement began in response to the killings of Trayvon Martin, Michael Brown, Eric Garner, and Rekia Boyd, among others. BLM and its related organizations typically advocate for various policy changes related to Black liberation and criminal justice reform. While there are specific organizations that label themselves "Black Lives Matter", such as the Black Lives Matter Global Network Foundation, the overall movement is a decentralized network with no formal hierarchy. As of 2021, there are about 40 chapters in the United States and Canada. The slogan "Black Lives Matter" itself has not been trademarked by any group.
In 2013, activists and friends Alicia Garza, Patrisse Cullors, and Ayọ Tometi originated the hashtag #BlackLivesMatter on social media following the acquittal of George Zimmerman in the fatal shooting of African-American teen Trayvon Martin. The movement became nationally recognized for street demonstrations following the 2014 deaths of two more African Americans, Michael Brown—resulting in protests and unrest in Ferguson, Missouri—and Eric Garner in New York City. Since the Ferguson protests, participants in the movement have demonstrated against the deaths of numerous other African Americans by police actions or while in police custody, in the summer of 2015. The movement gained international attention during global protests in 2020 following the murder of George Floyd by Minneapolis police officer Derek Chauvin. An estimated 15 to 26 million people participated in Black Lives Matter protests in the United States, making it one of the largest protest movements in the country's history. The vast majority of BLM demonstrations in 2020 were peaceful, but BLM protests from late May to early June 2020 escalated into riots and looting in most major cities.