MS-13, also known as Mara Salvatrucha, is an international criminal gang that originated in Los Angeles, California, in the 1980s. It was initially formed to protect Salvadoran immigrants from other gangs, and later developed into a more traditional criminal organization.

After the Salvadoran Civil War ended in 1992, deportations of gang members to El Salvador helped the gang spread into Central America. MS-13 has also been active in parts of the United States, Canada and Mexico. It has a longstanding rivalry with the 18th Street gang, known in El Salvador as Barrio 18.

In El Salvador, President Nayib Bukele has cited MS-13 and Barrio 18 as reasons for maintaining the state of emergency imposed in 2022 as part of a campaign against violent gangs.