Operation Southern Move (Croatian: Operacija Južni potez) was the final Croatian Army (HV) and Croatian Defence Council (HVO) offensive of the Bosnian War. It took place in western Bosnia and Herzegovina on 8–11 October 1995. Its goal was to help the Army of the Republic of Bosnia and Herzegovina (ARBiH) whose positions around the town of Ključ, captured by them during Operation Sana, were endangered by a counteroffensive by the Army of Republika Srpska (VRS). The objectives of Operation Southern Move included the capture of the town of Mrkonjić Grad and positions on the Manjača Mountain which would allow the HV and the HVO to directly threaten Banja Luka, the largest city controlled by Bosnian Serbs. Finally, the offensive was also aimed at capturing the Bočac Hydroelectric Power Station, the last significant source of electricity under VRS control in western Bosnia and Herzegovina. The combined HV and HVO forces were under the overall command of HV Major General Ante Gotovina.

The offensive achieved its objectives, and significantly contributed, along with Operations Sana and Maestral 2, to forcing the Bosnian Serb leadership to serious peace negotiations. The offensive also contributed to the displacement of 10,000 Bosnian Serb refugees and resulted in the deaths of at least 181 Serbs while hundreds more went missing following the operation. A country-wide ceasefire came into effect on 12 October, one day after the offensive ended, and was soon followed by negotiations which produced the Dayton Agreement, ending the Bosnian War.

As the Yugoslav People's Army (Jugoslovenska narodna armija – JNA) withdrew from Croatia following the acceptance and start of implementation of the Vance plan, its 55,000 officers and soldiers born in Bosnia and Herzegovina were transferred to a new Bosnian Serb army, which was later renamed the Army of Republika Srpska (Vojska Republike Srpske – VRS). This re-organisation followed the declaration of the Serbian Republic of Bosnia and Herzegovina on 9 January 1992, ahead of the referendum on the independence of Bosnia and Herzegovina that took place between 29 February and 1 March 1992. This declaration would later be cited by the Bosnian Serbs as a pretext for the Bosnian War. Bosnian Serbs began fortifying the capital, Sarajevo, and other areas on 1 March 1992. On the following day, the first fatalities of the war were recorded in Sarajevo and Doboj. In the final days of March, Bosnian Serb forces bombarded Bosanski Brod with artillery, resulting in a cross-border operation by the Croatian Army (Hrvatska vojska – HV) 108th Brigade. On 4 April 1992, JNA artillery began shelling Sarajevo. There were other examples of the JNA directly supported the VRS, such as during the capture of Zvornik in early April 1992, when the JNA provided artillery support from Serbia, firing across the Drina River. At the same time, the JNA attempted to defuse the situation and arrange negotiations elsewhere in the country.

The JNA and the VRS in Bosnia and Herzegovina faced the Army of the Republic of Bosnia and Herzegovina (Armija Republike Bosne i Hercegovine – ARBiH) and the Croatian Defence Council (Hrvatsko vijeće obrane – HVO), reporting to the Bosniak-dominated central government and the Bosnian Croat leadership respectively, as well as the HV, which occasionally supported HVO operations. In late April 1992, the VRS was able to deploy 200,000 troops, hundreds of tanks, armoured personnel carriers (APCs) and artillery pieces. The HVO and the Croatian Defence Forces (Hrvatske obrambene snage – HOS) could field approximately 25,000 soldiers and a handful of heavy weapons, while the ARBiH was largely unprepared with nearly 100,000 troops, small arms for less than a half of their number and virtually no heavy weapons. Arming of the various forces was hampered by a United Nations (UN) arms embargo that had been introduced in September 1991. By mid-May 1992, when those JNA units which had not been transferred to the VRS withdrew from Bosnia and Herzegovina to the newly declared Federal Republic of Yugoslavia, the VRS controlled approximately 60 percent of Bosnia and Herzegovina. The extent of VRS control was extended to about 70 percent of the country by the end of 1992.

By 1995, the ARBiH and the HVO had developed into better-organised forces employing comparably large numbers of artillery pieces and good defensive fortifications. The VRS was not capable of penetrating their defences even where its forces employed sound military tactics, for instance in the Battle of Orašje in May and June 1995. After recapture of the bulk of the Republic of Serb Krajina (the Croatian Serb-controlled areas of Croatia) in Operation Storm in August 1995, the HV shifted its focus to western Bosnia and Herzegovina. The shift was motivated by a desire to create a security zone along the Croatian border, establish Croatia as a regional power and gain favours with the West by forcing an end to the Bosnian War. The government of Bosnia and Herzegovina welcomed the move as it contributed to their goal of gaining control over western Bosnia and the city of Banja Luka—the largest city in the Bosnian Serb-held territory.

In the final days of August 1995, NATO launched Operation Deliberate Force—an air campaign targeting the VRS. This campaign was launched in response to the second Markale massacre of 28 August, which came on the heels of the Srebrenica massacre. Airstrikes began on 30 August, initially targeting VRS air defences, and striking targets near Sarajevo. The campaign was briefly suspended on 1 September and its scope was expanded to target artillery and storage facilities around the city. The bombing resumed on 5 September, and its scope extended to VRS air defences near Banja Luka by 9 September as NATO had nearly exhausted its list of targets near Sarajevo. On 13 September, the Bosnian Serbs accepted NATO's demand for the establishment of an exclusion zone around Sarajevo and the campaign ceased.

Following a relative lull in fighting in western Bosnia, the HV, HVO and ARBiH renewed their joint offensive against the VRS in the region. The HV and HVO component of the offensive, codenamed Operation Maestral 2, was launched on 8 September with the aim of capturing the towns of Jajce, Šipovo and Drvar. The ARBiH 7th Corps advanced on the right flank of the HV and the HVO towards Donji Vakuf. As Operation Maestral 2 neared its objectives, the ARBiH 5th Corps launched Operation Sana in the Bihać area, aimed at pushing the VRS back to the Sana River to the east. The ARBiH achieved significant territorial gains, advancing 70 kilometres (43 miles) to capture the town of Ključ, and approaching Sanski Most and Novi Grad by 18–19 September—before being halted by significant VRS reinforcements. A VRS counteroffensive, launched on the night of 23/24 September from Novi Grad, Sanski Most and Mrkonjić Grad gradually pushed the 5th Corps back towards Bosanska Krupa and Ključ, despite gradual arrival of reinforcements dispatched by the ARBiH 7th Corps. The VRS had approached within 1,000 metres (3,300 feet) of Ključ by 6 October, and ARBiH control of the town was under threat. In response, the ARBiH requested HV and HVO assistance.

The HV and the HVO forces earmarked for the offensive comprised 11,000–12,000 troops, organised into two groups, under the overall command of HV Major General Ante Gotovina. The primary group consisted of the 4th Guards and the 7th Guards Brigades, the 1st Croatian Guards Brigade (1. hrvatski gardijski zdrug – 1st HGZ) of the HV, while the second group was spearheaded by the 1st, 2nd and 3rd Guards Brigades of the HVO, and included the 126th Home Guard Regiment of the HV.