装甲巡洋舰是十九世纪晚期到20世纪初期的一种巡洋舰，它的火力能击败战列舰外的所有舰种而面对战列舰时又有足够速度逃跑。尽管大小各有不同，该种舰与同时代的另一巡洋舰主要分类---防护巡洋舰的区别就是两侧船壳有装甲带来保护自己。最早的此舰是沙俄海军的General-Admiral, 1873年下水使用风帆-汽轮混合动力。

1890年代，出现了表面硬化装甲使得军舰能用较少的重量得到较高防护。一战前出现了取代它的战列巡洋舰，从此它便衰落，有少数存活到了二战。

The armored cruiser was a type of warship of the late 19th and early 20th centuries. It was designed like other types of cruisers to operate as a long-range, independent warship, capable of defeating any ship apart from a battleship and fast enough to outrun any battleship it encountered. Varying in size, it was distinguished from other types of cruiser by its belt armor—thick iron (or later steel) plating on much of the hull to protect the ship from shellfire much like that on battleships. The first armored cruiser, the Imperial Russian Navy's General-Admiral, was launched in 1873 and combined sail and steam propulsion. By the 1890s cruisers had abandoned sail and took on a modern appearance.