The UR-100 () was an intercontinental ballistic missile (ICBM) developed and deployed by the Soviet Union from 1966 to 1996. УР in its designation stands for "универсальная ракета" ("universal rocket"). It was known during the Cold War by the NATO reporting name SS-11 Sego and internally by the GRAU index 8K84. The similar designation UR-100MR actually refers to an entirely different missile, the MR-UR-100 Sotka (SS-17 Spanker).