The Mogami class (最上型) was a ship class of four cruisers built for the Imperial Japanese Navy (IJN) during the 1930s. They were initially classified as light cruisers under the weight and armament restrictions of the London Naval Treaty. After Japan abrogated that agreement, all four ships were rearmed with larger guns and reclassified as heavy cruisers. All participated in World War II and were sunk.

A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several operational roles from search-and-destroy to ocean escort to sea denial.