MARC standards, a data format used for library cataloging,
MARC Train, a regional commuter rail system serving Maryland, Washington, D.C., and eastern West Virginia
MARC (archive), a computer-related mailing list archive
M/A/R/C Research, a marketing research and consulting firm
Massachusetts Animal Rights Coalition, a non-profit, volunteer organization
Matador Automatic Radar Control, a guidance system for the Martin MGM-1 Matador cruise missile
Mid-America Regional Council, the Council of Governments and the Metropolitan Planning Organization for the bistate Kansas City region
Midwest Association for Race Cars, a former American stock car racing organization
Revolutionary Agrarian Movement of the Bolivian Peasantry ( Movimiento Agrario Revolucionario del Campesinado Boliviano), a defunct right-wing political movement
Mid-Atlantic Rowing Conference, a college rowing conference.
