All or nothing is a method of naval warship armor, best known for its employment on dreadnought battleships. The concept involves heavily armoring the areas most important to a ship while the rest of the ship receives no armor. The "all or nothing" concept avoided light or moderate thicknesses of armor: armor was used in the greatest practicable thickness or not at all, thereby providing "either total or negligible protection". Compared to previous armoring systems, "all or nothing" ships had thicker armor covering a smaller proportion of the hull.

USS Nevada (BB-36), the third United States Navy ship to be named after the 36th state, was the lead ship of the two Nevada-class battleships. Launched in 1914, Nevada was a leap forward in dreadnought technology; four of her new features would be included on almost every subsequent US battleship: triple gun turrets, oil in place of coal for fuel, geared steam turbines for greater range, and the "all or nothing" armor principle. These features made Nevada, alongside her sister ship Oklahoma, the first US Navy "standard-type" battleships.