The Yorktown class was a class of three aircraft carriers built for the United States Navy and completed shortly before World War II, the Yorktown (CV-5), Enterprise (CV-6), and Hornet (CV-8). They immediately followed Ranger, the first U.S. aircraft carrier built as such, and benefited in design from experience with Ranger and the earlier Lexington class, which were conversions into carriers of two battlecruisers that were to be scrapped to comply with the Washington Naval Treaty, an arms limitation accord.

These ships bore the brunt of the fighting in the Pacific during 1942, and two of the three were lost: Yorktown, sunk on 07 June 1942 after the Battle of Midway, and Hornet, later heavily damaged by the Japanese at the Battle of the Santa Cruz Islands, was unsuccessfully scuttled by the US Navy and left to be sunk by the Japanese.

Enterprise, the sole survivor of the class, was the most decorated ship of the U.S. Navy in the Second World War. After efforts to save her as a museum ship failed, she was scrapped in 1958.

After the commissioning of the two 33,000 [long] ton (33,530-tonne) Lexington class ships in 1927-28 there was a strong sentiment within the Navy that the remaining 69,000 tons (70,107 tonnes) of carriers allowed under the Washington Naval Treaties should be built as quickly as possible. The idea that the additional tonnage should come in the form of multiple ships built to a single design was also widely accepted, but different factions advocated for three different packages--either five ships, displacing 13,800 tons (14,021 tonnes) each; or four ships, displacing 17,250 tons (17,527 tonnes) each; or three ships, displacing 23,000 tons (23,369 tonnes) each. The consensus as of the late 1920s was that the largest number of decks would offer the greatest total aircraft capacity, and a decision was therefore made to order the five small carriers. For once government parsimony proved beneficial: Congress, on 13 February 1929, authorized construction of only one of the 13,800-ton carriers, which became Ranger. Years would pass before funding for additional carriers was approved, and by the time it was, experience with Lexington and Saratoga had demonstrated the pronounced advantages of larger carriers, to such a degree that, even before Ranger was commissioned, the selection of such a small, slow, and poorly protected design was widely considered to have been unwise.

The desirability of larger size having been settled on, in the early 1930s the question of exactly how to use up the tonnage remaining under Washington Treaty limits arose once again, leading to the development of a new series of schemes. Factoring in Ranger, designers now had approximately 55,200 tons (56,086) tonnes left to work with. Again, one faction argued for the creation of a uniform class, now to consist of three 18,400-ton (18,695-tonne) carriers, to fill the quota, but a strong opposing faction wanted to incorporate more of the features found on the much larger Lexingtons (high speed, torpedo protection, and an armored belt, any one of which would have been difficult to accommodate on an 18,400-ton displacement) into at least some ships. The General Board eventually settled on the idea of building two fairly large (c. 20,000-ton/20,321 tonne) carriers incorporating 32.5-knot speed, armor, and substantial underwater protection, and one smaller, c.15,000-ton (15,241-tonne) vessel, broadly similar to the large ones but lacking the protective features. The smaller carrier would eventually become Wasp, while the larger two became Yorktown and Enterprise. General designs for these two classes of ship were chosen from among a common slate of 15 draft designs presented to the General Board in 1931 by the Bureau of Construction and Repair. All 15 of these schemes included islands, long opposed by the Bureau of Aeronautics, but, thanks to operational experience accumulated with the Lexingtons by 1931, now considered desirable. Funding for construction of the two larger ships came with the National Recovery Act, passed on June 16, 1933, and Yorktown was laid down on May 21, 1934, two weeks before Ranger was commissioned. Enterprise was laid down on July 16, 1934. Work on the smaller Wasp was delayed for some time, but was ultimately authorized under the Vinson-Trammel Act of 1934, and construction, to essentially the specification laid out in 1931, began in 1936.

Two days after Enterprise was commissioned, in May 1938, partly in response to the withdrawal of Italy and Japan from the global naval arms limitation treaty structure, Congress passed the Naval Act of 1938, which authorized a major expansion of the Navy, including construction of 40,200 additional tons (40,845 tonnes) of aircraft carriers. After considerable debate and dithering the Navy decided that, in order to get a ship in service as quickly as possible, roughly half of this extra tonnage would be given over to building a third ship to a minimally modified Yorktown design, while time was spent figuring out how best to use the remainder. The third Yorktown-class ship, Hornet, was ordered in March 1939 and commissioned only a month before Pearl Harbor.

The Yorktowns were built with a transverse catapult on their hangar decks; these could launch aircraft in a direction perpendicular to the direction of the ship's motion, or while the ship was at anchor. These catapults were intended as substitutes for the lower-level flying-off decks that had been adopted by the British and Japanese in the 1920s, which allowed aircraft to be launched straight forward off both the upper flight deck and the deck below it at the same time, allowing the launch of more aircraft quickly in a scramble situation. Statements that the transverse catapults were intended to be used primarily for the launching of scout planes appear to be unfounded; all readily available photos of these catapults in use depict the launching of fighter aircraft, rather than scouts. In practice the U. S. commanders rarely used the hangar-deck catapults because of the difficulties inherent in controlling a plane launched across a heavy cross-wind, which would inevitably be faced when the ship was moving forward at high speed to allow aircraft to be flown off the axial flight deck at the same time. The hangar-deck catapults were removed from Enterprise and Hornet in late June 1942.

All three ships of the Yorktown class were built at the Newport News Shipbuilding Company, Newport News, Virginia.^{[citation needed]}