An affinity group is a small, autonomous group organized by mutual trust and shared analysis rather than formal membership, bylaws, or hierarchy. Affinity groups are the basic organizational unit of insurrectionary anarchism and are used across anarchist and direct-action movements for coordinating direct action.
The affinity group model reflects anarchist organizational principles: decisions are made by those who carry them out, trust is built through shared experience rather than institutional position, and the group exists to act rather than to perpetuate itself. Groups typically range from three to fifteen people who know each other personally and can make decisions quickly without formal process. Multiple affinity groups may coordinate through spokescouncils for larger actions while maintaining their internal autonomy.
The strength of the model is its resistance to infiltration and co-optation — there is no central leadership to compromise, no membership list to subpoena, no organizational continuity that depends on any single person. This is also why state counterinsurgency programs like COINTELPRO invested heavily in snitch-jacketing: when trust is the organizational principle, destroying trust is the most effective attack.