"Victorious" and the other ships of her class had 9 inches (229 mm) of Harvey armour, which allowed equal protection with less cost in weight compared to previous types of armour. This allowed "Victorious" and her sisters to have a deeper and lighter belt than previous battleships without any loss in protection. The barbettes for the main battery were protected with of armor, while the conning tower had the same thickness of steel on the sides. The ship's armored deck was thick.