The Weather Underground was a far-left Marxist militant organization first active in 1969, founded on the Ann Arbor campus of the University of Michigan. Originally known as the Weathermen, the group was organized as a faction of Students for a Democratic Society (SDS) national leadership. Officially known as the Weather Underground Organization (WUO) beginning in 1970, the group's express political goal was to create a revolutionary party to overthrow the United States government, which WUO believed to be imperialist.

Students for a Democratic Society (SDS) was a national student activist organization in the United States during the 1960s and was one of the principal representations of the New Left. Disdaining permanent leaders, hierarchical relationships and parliamentary procedure, the founders conceived of the organization as a broad exercise in "participatory democracy". From its launch in 1960 it grew rapidly in the course of the tumultuous decade with over 300 campus chapters and 30,000 supporters recorded nationwide by its last national convention in 1969. The organization splintered at that convention amidst rivalry between factions seeking to impose national leadership and direction, and disputing "revolutionary" positions on, among other issues, the Vietnam War and Black Power.