The Alaska class was a class of six large cruisers ordered before World War II for the United States Navy. They were officially classed as large cruisers (CB), but others have regarded them as battlecruisers. They were all named after territories or insular areas of the United States, signifying their intermediate status between larger battleships and smaller heavy and light cruisers.[C] Of the six planned, two were completed, the third's construction was suspended on 16 April 1947, and the last three were cancelled. Alaska and Guam served with the U.S. Navy for the last year of World War II as bombardment ships and fast carrier escorts. They were decommissioned in 1947 after spending only 32 and 29 months in service, respectively.

The idea for a large cruiser class originated in the early 1930s when the U.S. Navy sought to counter Deutschland-class "pocket battleships" being launched by Germany. Planning for ships that eventually evolved into the Alaska class began in the late 1930s after the deployment of Germany's Scharnhorst-class battleships and rumors that Japan was constructing a new battlecruiser class. To serve as "cruiser-killers" capable of seeking out and destroying these post-treaty heavy cruisers, the class was given large guns of a new and expensive design, limited armor protection against 12-inch shells, and machinery capable of speeds of about 31–33 knots (57–61 km/h; 36–38 mph).