Never Again MSD is an American student-led political action committee for gun control that advocates for tighter regulations to prevent gun violence. The organization, also known by the Twitter hashtags #NeverAgain, and #EnoughIsEnough, was formed by a group of twenty students attending Marjory Stoneman Douglas High School (MSD) at the time of the deadly shooting in 2018, in which seventeen students and staff members were killed by the alleged gunman, Nikolas Cruz, who was a 19-year-old former student of the school and was armed with an AR-15 style semi-automatic rifle. The organization started on social media as a movement "for survivors of the Stoneman Douglas Shooting, by survivors of the Stoneman Douglas Shooting" using the hashtag #NeverAgain. A main goal of the group was to influence that year's United States mid-term elections, and they embarked on a multi-city bus tour to encourage young people to register to vote.

Gun violence is a term of political, economic and sociological interest referring to the tens of thousands of annual firearms-related deaths and injuries occurring in the United States. In 2022, up to 100 daily fatalities and hundreds of daily injuries were attributable to gun violence in the United States. In 2018, the most recent year for which data are available, the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics reported 38,390 deaths by firearm, of which 24,432 were suicides. The national rate of firearm deaths rose from 10.3 people for every 100,000 in 1999 to 11.9 people per 100,000 in 2018, equating to over 109 daily deaths. In 2010, there were 19,392 firearm-related suicides, and 11,078 firearm-related homicides in the U.S. In 2010, 358 murders were reported involving a rifle while 6,009 were reported involving a handgun; another 1,939 were reported with an unspecified type of firearm. In 2011, a total of 478,400 fatal and nonfatal violent crimes were committed with a firearm.