The Capture of Jenin occurred on 20 September 1918, during the Battle of Sharon which together with the Battle of Nablus formed the set piece Battle of Megiddo fought between 19 and 25 September during the last months of the Sinai and Palestine Campaign of World War I. During the cavalry phase of the Battle of Sharon carried out by the Desert Mounted Corps, the 3rd Light Horse Brigade, Australian Mounted Division attacked and captured the town of Jenin located on the southern edge of the Esdraelon Plain (also known as the Jezreel Valley and the plain of Armageddon) 40–50 miles (64–80 km) behind the front line in the Judean Hills. The Australian light horse captured about 2,000 prisoners, the main supply base and the ordnance depot of the Seventh and the Eighth Armies in and near the town. They also cut the main road from Nablus and a further 6,000 Ottoman Empire and German Empire prisoners, were subsequently captured as they attempted to retreat away from the Judean Hills.

The Egyptian Expeditionary Force (EEF) cavalry had ridden through a gap on the Mediterranean Sea coast, created by the infantry during the Battle of Tulkarm, to capture the two Ottoman armies' main lines of communication and supply north of the Judean Hills, while the infantry battles continued. On 20 September, the Desert Mounted Corps captured Afulah, Beisan and Jenin on the Esdrealon Plain. The next day the headquarters of the Seventh Army at Nablus, and the General Headquarters (GHQ) of the Yilderim Army Group at Nazareth, were both captured, while Haifa was captured two days later. During a subsequent early morning attack on 25 September, a German rearguard was captured during the Battle of Samakh, which ended the Battle of Sharon. During these operations the greater part of one Ottoman army was captured in the Judean Hills and at Jenin. These and other battles fought during the Battle of Megiddo including the Battle of Nablus and Third Transjordan attack, forced the retreating Ottoman Fourth, and remnants of the Seventh and the Eighth Armies, to the eastern side of the Jordan River. As they withdrew northwards towards Damascus they were pursued by the Desert Mounted Corps.

After the infantry established a gap in the Ottoman front line on the coast early on the morning of 19 September, the Australian Mounted Division's 3rd and 4th Light Horse Brigades (less the 5th Light Horse Brigade temporarily detached to the 60th Division) in reserve, followed the 4th Cavalry Division north on the Plain of Sharon and across the Mount Carmel Range, by the Musmus Pass, to Lejjun on the Esdrealon Plain. While the 4th Light Horse Brigade remained to garrison Lejjun and provide various guards for artillery, supplies, and corps headquarters before being ordered to capture Samakh, the 3rd Light Horse Brigade advanced to Jenin, where the 9th and 10th Light Horse captured the town after a brief fire fight. Subsequently, these two regiments captured some 8,000 Ottoman soldiers, who had been attempting to retreat northwards out of the Judean Hills, during the night of 20/21 September. The outnumbered Australian Light Horsemen were reinforced as quickly as possible, and the majority of the prisoners were marched back into holding camps, near Lejjun in the morning. The 3rd Light Horse Brigade remained in the area to garrison Jenin until they advanced to capture Tiberias on 25 September 1918, before participating in the pursuit to Damascus.

Following the Capture of Jericho in February, the commander of the Egyptian Expeditionary Force (EEF), General Edmund Allenby ordered the occupation of the Jordan Valley. In March–April and April–May 1918, the First and the Second Transjordan attacks took place, while the front line across the Judean Hills to the Mediterranean Sea was defended. During this time, three-quarters of the British infantry and yeomanry cavalry regiments were redeployed to the Western Front to counter Ludendorff's German spring offensive. They were replaced by British India Army infantry and cavalry which required a reorganisation. These newly arrived soldiers carried out a series of attacks on sections of the Ottoman front line in the Judean Hills during the summer months, as part of their training. These attacks including the Battle of Tell 'Asur and Action of Berukin in March and April, were aimed at pushing the front line to more advantageous positions in preparation for a major attack, and to acclimatise the newly arrived infantry. This fighting continued during the summer months. By the middle of September the consolidated EEF was once again ready for large-scale offensive operations.

On 19 September, the Battle of Megiddo commenced with the XXI Corps (commanded by Lieutenant General Edward Bulfin), under cover of a creeping barrage, broke through the Ottoman front line to begin the Battle of Sharon. In the afternoon the XX Corps commanded by Lieutenant General Philip Chetwode began the Battle of Nablus, also supported by an artillery barrage. This offensive by the XX and XXI Corps, continued until midday on 21 September, when a successful flanking attack by the XXI Corps, combined with the XX Corps assault, forced the Seventh and the Eighth Armies, to disengage. The Seventh Army retreated from the Nablus area towards the Jordan River, crossing at the Jisr ed Damieh bridge before a rearguard at Nablus was captured. While the EEF infantry were fighting the Seventh and Eighth Armies in the Judean Hills, the Desert Mounted Corps commanded by the Australian Lieutenant General Harry Chauvel advanced through the gap created by the XXI Corps infantry on the morning of 19 September, to ride northwards and virtually encircle the Ottoman forces before they disengaged. The cavalry divisions captured Nazareth, Haifa, Afulah, Beisan, and Jenin before and Samakh and the Capture of Tiberias ended the Battle of Megiddo. During this time, Chaytor's Force (temporarily detached from Desert Mounted Corps) commanded by Major General Edward Chaytor, captured part of the retreating Ottoman and German column at the Capture of Jisr ed Damieh bridge over the Jordan River to cut off this line of retreat, during the Third Transjordan attack. To the east of the river, as the Ottoman Fourth Army began its retreat, Chaytor's Force advanced to capture Es Salt on 23 September and Amman on 25 September. Units of Chaytor's Force captured Amman after defeating a strong Fourth Army rearguard during the Second Battle of Amman.

In preparation for the Battle of Megiddo, the Desert Mounted Corps, consisting of the 4th and 5th Cavalry Divisions, the Australian Mounted Division's 3rd and 4th Light Horse Brigades, concentrated near Ramleh, Ludd (Lydda), and Jaffa. Here dumps were formed of all surplus equipment, before the brigades and divisions moved up close behind the XXI Corps infantry divisions, near the Mediterranean coast.

Each mounted division of about 3,500 troopers, consisted of three brigades, each brigade being made up of three regiments. Five of the six brigades of the 4th and 5th Cavalry Divisions, most of which had recently arrived from France, consisted of one British yeomanry regiment and two British Indian Army cavalry regiments, one of which was usually lancers, including the Indian Princely States' 15th Imperial Service Cavalry Brigade of three lancer regiments. Some of the cavalry regiments were armed in addition to their Lee–Enfield rifles, bayonets and swords, with lances. The Australian Mounted Division consisting of three light horse brigades, each with three regiments, containing a headquarters and three squadrons. With 522 men and horses in each regiment, they were armed in addition to their rifles and bayonets with swords. The mounted divisions were supported by machine gun squadrons, three artillery batteries from the Royal Horse Artillery or the Honourable Artillery Company, and light armoured car units—two Light Armoured Motor Batteries, and two Light Car Patrols.

By 17 September the 5th Cavalry Division, which would lead the advance, was deployed north-west of Sarona, eight miles (13 km) from the front line, with the 4th Cavalry Division in orange groves to the east, ten miles (16 km) from the front, and the Australian Mounted Division in reserve near Ramleh and Ludd, 17 miles (27 km) from the front line. All movement, restricted to the night hours, culminated in a general move forward on the eve of battle during the night of 18/19 September, when the Australian Mounted Division moved up to Sarona. The supplies for the three divisions concentrated in the rear in divisional trains, in massed horse-drawn transport and on endless strings of camels, clogging every road in the area. One iron ration and two days' special emergency ration for each man, and 21 pounds (9.5 kg) of grain for each horse, was carried on the trooper's horse, with an additional day's grain for each horse, carried on the first-line transport limbered wagons.