The Lockheed C-130 Hercules is a four-engine turboprop military transport aircraft built by Lockheed. Capable of using unprepared runways for takeoffs and landings, the C-130 was originally designed as a troop, medical evacuation, and cargo transport aircraft. The versatile airframe has found uses in a variety of other roles, including as a gunship, for airborne assault, search and rescue, scientific research support, weather reconnaissance, aerial refueling, maritime patrol and aerial firefighting. It is the main tactical airlifter for many military forces worldwide. Over 40 models and variants of the Hercules serve with more than 50 nations.

During its years of service the Hercules family has participated in countless military, civilian and humanitarian aid operations. The family has the longest continuous production run of any military aircraft in history. In 2007, the C-130 became the fifth aircraft—after the English Electric Canberra, B-52 Stratofortress, Tupolev Tu-95, and KC-135 Stratotanker—to mark 50 years of continuous use with its original primary customer, in this case, the United States Air Force. The C-130 is also the only military aircraft to remain in continuous production for 50 years with its original customer, as the updated C-130J Super Hercules.

The Korean War, which began in June 1950, showed that World War II-era transports—C-119 Flying Boxcars, C-47 Skytrains and C-46 Commandos—were inadequate for modern warfare. Thus on 2 February 1951, the United States Air Force issued a General Operating Requirement (GOR) for a new transport to Boeing, Douglas, Fairchild, Lockheed, Martin, Chase Aircraft, North American, Northrop, and Airlifts Inc. The new transport would have a capacity for 92 passengers, 72 combat troops or 64 paratroopers, a range of 1,100 nmi (1,300 mi; 2,000 km), takeoff capability from short and unprepared strips, and the ability to fly with one engine shut down.

Fairchild, North American, Martin and Northrop declined to participate. The remaining five companies tendered a total of ten designs: Lockheed two, Boeing one, Chase three, Douglas three, and Airlifts Inc. one. The contest was a close affair between the lighter of the two Lockheed (preliminary project designation L-206) proposals and a four-turboprop Douglas design.

The first flight of the YC-130 prototype was made on 23 August 1954 from the Lockheed plant in Burbank, California. The aircraft, serial number 53-3397, was the second prototype but the first of the two to fly. The YC-130 was piloted by Stanley Beltz and Roy Wimmer on its 61-minute flight to Edwards Air Force Base; Jack Real and Dick Stanton served as flight engineers. Kelly Johnson flew chase in a P2V Neptune.

The initial production model, the C-130A, was powered by Allison T56-A-9 turboprops with three-blade propellers. Deliveries began in December 1956, continuing until the introduction of the C-130B model in 1959. Some A models were re-designated C-130D after being equipped with skis. The newer C-130B had ailerons with increased boost — 3,000 psi (21 MPa) versus 2,050 psi (14 MPa) — as well as uprated engines and four-bladed propellers that were standard until the J-model's introduction.

The Hercules holds the record for the largest and heaviest aircraft to land on an aircraft carrier. In October and November 1963, a USMC KC-130F (BuNo 149798), bailed to the US Naval Air Test Center, made 29 touch-and-go landings, 21 unarrested full-stop landings and 21 unassisted take-offs on the USS Forrestal at a number of different weights. The pilot, LT (later RADM) James Flatley III, USN, was awarded the Distinguished Flying Cross for his role in this test series. The tests were highly successful, but the idea was considered too risky for routine "Carrier Onboard Delivery" (COD) operations. Instead, the C-2 Greyhound was developed as a dedicated COD aircraft. The Hercules used in the test, most recently in service with Marine Aerial Refueler Squadron 352 (VMGR-352) until 2005, is now part of the collection of the National Museum of Naval Aviation at NAS Pensacola, Florida.