The two ships of the Pennsylvania-class were the most modern US battleships at the outbreak of World War I and represented a further refinement of the super-dreadnought concept that began with the preceding Nevada-class. Compared to the Nevadas, the Pennsylvania ships had two extra guns for a total of twelve 14-in guns in four triple turrets. Secondary armament consisted of 5-in/51 guns mounted in casemates but these proved to be susceptible to bad weather; this would be the last US battleship class in which at least part of the armament was not located in higher decks. Armor protection followed the 'all-or-nothing' concept that began with its predecessors. Both ships were given extensive modernizations in the in interwar period, which involved upgrades to the main batteries (higher elevation), new anti-aircraft armament, fire control systems, anti-torpedo bulges, and a new propulsion system. The two ships did not participate in World War I given the preference for coal-burning ships to be sent to the front lines (due to a shortage of oil in the UK). Both were in Pearl Harbor during the Japanese attack where the USS Arizona suffered a fatal magazine explosion. It sister, the USS Pennsylvania participated in the Pacific campaign and was sunk as a target after the war.

The USS Pennsylvania suffered severe damage at Pearl Harbor and underwent a refit before serving in the Aleutians and the later island hopping campaigns. It was in action in the Surigao Strait during the Battle of Leyte Gulf. After the war it was used during the Bikni atoll atomic tests but survived. It was then used for radiological testing before being sunk as a target in 1948. The USS Arizona was less fortunate: it suffered numerous bomb hits during the Pearl Harbor attack, one of which resulted in a catastrophic magazine explosion. It therefore became one of the two US battleships to have been lost in combat during the war.