Design B-65 was a class of Super Type A cruisers planned by the Imperial Japanese Navy (IJN) before and during World War II. As envisioned by the IJN, the cruisers were to play a key role in the Night Battle Force portion of the "Decisive battle" strategy which Japan hoped, in the event of war, to employ against the United States Navy.

Begun in 1939, plans were far enough along that tests were conducted with the main armament and against the underwater protection. Even though the ships were approved for construction under a 1942 fleet replenishment program, the prioritizing of aircraft carriers and smaller ships due to the war, followed by Japan's defeat, killed any chance of the B-65's construction.

B65型超甲型巡洋艦（超甲巡、en:Design B-65 cruiser）とは、日本海軍が計画した巡洋艦または巡洋戦艦である。

老朽化した金剛型戦艦の代艦として、夜戦で水雷戦隊を支援する役割を与えられる予定であった。巡洋戦艦並みの船体と装備を持ち、大和型戦艦に類似した外観を持つ。 第五次海軍軍備充実計画（マル5計画）で2隻の建造が計画された。本型は、マル5計画から改マル5計画への見直しの際に航空母艦（空母）の重要さから計画から削除され、2隻とも建造中止となった。