The S-75 Dvina (Russian: ?-75; NATO reporting name SA-2 Guideline) is a Soviet-designed; high-altitude; command guided; surface-to-air missile (SAM) system. Since its first deployment in 1957; it has become the most widely-deployed and -used air defense missile in history; scoring the first successful engagement of an enemy aircraft by a SAM ever; shooting down a Taiwanese RB-57D over China; on October 7; 1959 by hitting it with three V-750 (1D) missiles at an altitude of 20 km (65;600 ft).

This system first gained international fame when an S-75 battery; using the newer; longer range and higher altitude V-750VN (13D) missile shot down the U-2 of Francis Gary Powers overflying the Soviet Union on May 1; 1960. The system was also deployed in Cuba during the Cuban Missile Crisis; where on October 27; 1962; it shot down the U-2 flown by Rudolf Anderson; almost precipitating a nuclear war.

Later; North Vietnamese forces used the S-75 extensively during the Vietnam War to defend Hanoi and Haiphong with some considerable success; especially during Operations Linebacker 1 and 2 in 1972. During these operations the PAVN claim 755 USAF aircraft destroyed including 34 B52 bombers; while the US admits to 159 aircraft lost including 16 B 52 bombers.