The R-36 (Russian: Р-36) is a family of intercontinental ballistic missiles (ICBMs) and space launch vehicles (Tsyklon) designed by the Soviet Union during the Cold War. The original R-36 was deployed under the GRAU index 8K67 and was given the NATO reporting name SS-9 Scarp. It was able to carry three warheads and was the first Soviet MIRV (multiple independently targetable re-entry vehicle) missile. The later version, the R-36M, also known as RS20, was produced under the GRAU designations 15A14 and 15A18 and was given the NATO reporting name SS-18 Satan. This missile was viewed by certain United States analysts as giving the Soviet Union first strike advantage over the U.S., particularly because of its rapid silo-reload ability, very heavy throw weight and extremely large number of re-entry vehicles. Some versions of the R-36M were deployed with 10 warheads and up to 40 penetration aids and the missile's high throw-weight made it theoretically capable of carrying more warheads or penetration aids. Contemporary U.S. missiles, such as the Minuteman III, carried up to three warheads at most.

The R-36 became the base for the Tsyklon launch vehicles family. As of early 2021, Cyclone-4M, the last Tsyklon variant in development, is planned for launch in 2023 from Canso, Nova Scotia.

Some R-36 missiles have been converted into Dnepr medium-lift launch vehicles, capable of putting up to 4,500 kg into orbit.

Development of the R-36 was begun by OKB-586 (Yuzhnoye) in Dnepropetrovsk, Ukraine (at the time part of the Soviet Union) in 1962, and built upon the work of the R-16 program. The Chief Designer was Mikhail Yangel. Initial development was of light, heavy, and orbital versions, with flight testing from 1962 through 1966, at which time initial operational capability was achieved. News of the development of the orbital version caused alarm in the West with the possibility that the Soviets would be able to launch a large number of nuclear weapons into orbit where there was no capability to intercept them. Weapons could potentially be left orbiting for an indefinite period. The prospect of orbital nuclear weapons led both sides to agree to a treaty banning the basing of weapons of mass destruction in space.

In 1970, development of a fourth version, capable of delivering multiple warheads, was begun, which was test flown the next year.

Further improvement of the R-36 led to the design of the R-36M, which provided a theoretical first-strike capability—the ability to destroy the United States' LGM-30 Minuteman ICBM silos and launch control centers before they could retaliate. However, neither the Soviet Union nor the Russian Federation have ever publicly delineated the missile's particular role in their arsenal. The initial design of the R-36M called for a single massive 12 Mt warhead to be delivered over a range of 10,600 km. The missile was first tested in 1973 but this test ended in failure. After several delays the R-36M was deployed in December 1975. This design was delivered with a single 18–20 Mt warhead and a range of just over 11,000 km. This new version was given a new codename by NATO: SS-18 Satan.

The R-36M has gone through six separate variants, with the first being phased out by 1984. The final variant designated R-36M-2 "Voevoda" (NATO codename SS-18 mod 6) was deployed in August 1988. This missile could deliver the same 18–20 Mt warhead 16,000 km. Prior variants mainly introduced MIRV (Multiple independent reentry vehicles) warheads. These missiles surpassed their western counterpart, the US LGM-118 Peacekeeper in terms of megatons delivered, range, and survivability, but were inferior in terms of accuracy (CEP).

The control system for this rocket was designed at NPO "Electropribor" (Kharkiv, Ukraine).