The Kh-55 (Russian: Х-55[note 1], also known as RKV-500; NATO reporting name: AS-15 "Kent") is a Soviet/Russian subsonic air-launched cruise missile, designed by MKB Raduga in the 1970s.

Kh-55 is launched exclusively from bomber aircraft and has spawned a number of conventionally armed variants mainly for tactical use, such as the Kh-65SE and Kh-SD, but only the Kh-555 appears to have been put into service.

[6] After the end of the Cold War and anti-proliferation treaties restricting the deployment of long-range nuclear missiles, the Russians made efforts to develop tactical versions of the Kh-55 with conventional warheads.

[3] A 1995 Russian document suggested that a complete production facility had been transferred to Shanghai, for the development of a nuclear-armed cruise missile.

[9] The original Kh-55 was powered by a drop-down, Ukrainian-made 400 kgf Motor Sich JSC R95-300 turbofan engine, with pop-out wings for cruising efficiency.

[16] In October 1999, a compromise was reached that saw Russia pay US$285 million for eight Tu-160 and three Tu-95MS bombers and 575 Kh-55 cruise missiles,[16] while the rest were meant to be destroyed under U.S.-led Nunn–Lugar Cooperative Threat Reduction programme.

[21][23][24][25] Russian news agency TASS reported on 17 November 2016 that modernized Tu-95MS armed with Kh-555 and Kh-101 air-launched cruise missiles had launched airstrikes against targets described as terrorist in Syria.

[26][27] The UK Ministry of Defence said in November 2022 that it appeared that Russian forces, due to very much depleted weapons stores, were firing old AS-15 Kent cruise missiles with the nuclear warheads apparently replaced by inert ballast, hoping merely to distract Ukrainian air defenses.

[34] It is not clear, if its fall in Poland, near aviation repair works in Bydgoszcz, engaged in military aid for Ukraine, was caused by a technical failure of an old missile, or was a provocation.