The amphibious Battle of Gela was the opening engagement of the American portion of the Allied Invasion of Sicily during World War II. United States Navy ships landed United States Army troops along the eastern end of the south coast of Sicily; and withstood attacks by Luftwaffe and Regia Aeronautica aircraft while defending the beachhead against attacks by Livorno Division and German Göring Division tanks until the US Army captured the Ponte Olivo Airfield for use by United States Army Air Forces planes. The battle convinced United States Army officers of the value of naval artillery support, and revealed problems coordinating air support from autonomous air forces during amphibious operations.

The invasion of Sicily followed the Allied capture of Tunisia in North Africa and preceded the Allied invasion of Italy as a means of diverting Axis forces from the eastern front with the Soviet Union until the Western Allies were prepared to invade occupied Europe through France. Ground forces under overall command of General Dwight D. Eisenhower were transported by naval forces under overall command of Admiral Andrew Cunningham. The invasion was constrained by marginally effective air cover from 670 Allied fighters operating at maximum range which limited patrolling time over one hundred miles of invasion beaches and prevented proportional response to incoming raids. There were three wings (twenty squadrons) of Supermarine Spitfires operating from airfields on Malta and two groups of Curtiss P-40 Warhawks from airfields on Pantelleria and Gozo. Allied air forces refused to provide air support for Allied ground forces until Axis air forces had been neutralized; and, since Axis bombing continued through 12 July, the role of Allied aircraft was negligible in the fighting at Gela. Pre-invasion strategic bombing reduced Luftflotte 2 strength to 175 planes in Sicily, but 418 additional Luftwaffe and 449 Regia Aeronautica aircraft remained serviceable at bases in Italy to be flown in as required.

Allied ground forces had no idea when, where, in what numbers, or under what circumstances they might see Allied aircraft. Unlike the earlier invasion of North Africa and later invasion of Italy, the United States invasion fleet included no aircraft carriers. Carriers which had supported the American landings during Operation Torch had been reassigned without replacement. The escort carrier USS Santee was defending UG convoys from U-boats while the other three Sangamon class escort carriers had been transferred to the Pacific to support the Guadalcanal campaign and the fleet carrier USS Ranger was training new pilots on the United States Atlantic coast.

The fishing town of Gela was on a limestone plateau at 150-foot (46 m) elevation behind a beach with a 900-foot (270 m) pier. Plains cultivated for grain extended inland behind the community of 32,000. The mouth of the Gela River was 1 mile (1.6 km) east of the pier and the mouth of the Acate River was 5 miles (8 km) east of the Gela River. The sand and stone beach between the rivers was from 10–30 yards (9–27 m) wide and backed by 900 yards (820 m) of dunes. The drainage divide between the two rivers was the 400-foot (120 m) Piano Lupo highland 7 miles (11 km) northeast of Gela with a strategic junction of roads including the coastal highway between Gela and Scoglitti and roads leading inland to Niscemi and Caltagirone.

The 52d Troop Carrier Wing of 222 Douglas C-47 Skytrains from North Africa carried the airborne 505th Infantry Regiment for a parachute drop over Piano Lupo. A western task force of 601 ships (including 130 warships and 324 landing craft and transports with 1,124 shipboard landing boats) under the command of Vice Admiral Henry Kent Hewitt carried the Seventh United States Army under the command of Lieutenant General George S. Patton. Both officers sailed aboard the flagship transport USS Monrovia. Patton commanded three times as many soldiers as Hewitt had landed eight months earlier at Morocco during Operation Torch. Americans had not previously sustained so many combat troops over beaches without a port; so the amphibious shipping included nine new types of landing boats, five new types of landing ships, and project Goldrush pontoon causeways untested under combat conditions. The invasion was the European combat premier of tank landing ships (LST)s only a week after the Pacific Operation Cartwheel. The western task force was divided into Task Force C to land the 3rd Infantry Division near Licata (sector Joss) on the western flank, Task Force K to land the 45th Infantry Division near Scoglitti (sector Cent) on the eastern flank, and Task Force H to land the 16th and 26th Regiments of the 1st Infantry Division with the 531st Engineers and the 1st 3rd and 4th Rangers, with the 83rd Chemical Mortar Battalion attached near Gela (sector Dime). The reserve force of the 2nd Armored Division and 18th Regiment of the 1st Infantry Division was landed on the first day of fighting to support the 1st Infantry Division.

The Gela invasion beaches were defended by the Italian 429th Coastal Battalion under Major Rubellino using barbed wire, concrete pillboxes, and anti-tank guns. The 429th Coastal Battalion was also defending the town itself. The beach on either side of the Gela pier was mined and defended by machine guns on both flanks and artillery batteries 7,000 yards (6,400 m) inland, on Cape Soprano to the west, and on Monte Lungo to the north. The sand and stone beach on the east side of the Gela River was defended by three machine gun nests at the east end and by artillery batteries 9,000 yards (8,200 m) to the north and 10,000 yards (9,100 m) to the northwest. The Italian 4th Infantry Division "Livorno" was positioned near Niscemi and supported by the Italian Mobile Group "E" at Ponte Olivo with obsolete R35 and Fiat tanks to respond when invasion points became known. They were joined on the afternoon of the first day by 9,000 German combat troops of the 1st Fallschirm-Panzer Division Hermann Göring with 46 Panzerkampfwagen III and 32 Panzerkampfwagen IV tanks from Caltagirone, reinforced with a regiment of the 15th Panzergrenadier Division with the schwere Panzer Abteilung 504 (s.Pz.Abt. 504) tank Battalion with 17 Tiger I tanks attached.

Air support was available from one staffel of Jagdgeschwader 53 Messerschmitt Bf 109G-6 fighters at Catania, two staffeln of Jagdgeschwader 77 Bf 109G-6 fighters at Trapani, another Jagdgeschwader 77 staffel at Sciacca, two staffeln of Schlachtgeschwader 2 Focke-Wulf Fw 190F-2 ground attack fighter-bombers at Castelvetrano, and two staffeln of Schnellkampfgeschwader 10 Fw 190A-5 fast bombers at Gerbini Airfield. Junkers Ju 88A and Savoia-Marchetti SM 79 medium bombers could reach Gela from bases in Italy.

The larger transports sailed from Oran on 5 July as convoy NCF 1 and were screened by destroyers as they hugged the African coast eastbound while the gunfire support cruisers sailed on a parallel course as a covering force to the north. The LSTs, LCIs, LCTs and patrol craft sailed directly from Tunisia as convoys TJM 1 and TJS 1. The convoys were spotted and all German forces on Sicily were alerted at 18:40 on 9 July. Beaufort scale force 7 winds created 12-foot (3.7 m) seas causing widespread seasickness among the embarked troops. Winds moderated on the evening of 9 July as ships divided into task forces C, H, and K and proceeded to assigned anchorages off the Sicilian coast. As the ships anchored, airborne troops of the 505th Infantry Regiment were scattered by wind and aircraft navigation errors. Fewer than 200 of the 3,400 paratroopers were able to reach the strategic Piano Lupo highland before the defending Livorno Division arrived.