The 9K111 Fagot is a second-generation tube-launched SACLOS wire-guided anti-tank missile system of the Soviet Union for use from ground or vehicle mounts. The 9K111 Fagot missile system was developed by the Tula KBP Design Bureau for Instrument Building. "9M111" is the GRAU designation of the missile. Its NATO reporting name is AT-4 Spigot.
The 9K111 Fagot was developed by the Tula Machinery Design Bureau (Tula KBP). Development began in 1962 with the aim of producing the next generation of SACLOS ATGMs for use in both the man portable role and the tank destroyer role. The 9K111 Fagot was developed alongside the 9M113 Konkurs; both missiles use similar technology – only differing in size - and can use the same launchers.
The missile entered service in 1970.