L 20e α was a design for a class of battleships to be built in 1918 for the German Kaiserliche Marine (Imperial Navy) during World War I.

Reinhard Scheer, the commander of the fleet, wanted larger main guns and a higher top speed than earlier vessels, to combat the latest ships in the British Royal Navy.

Germany's declining war situation and the reallocation of resources to support the U-boat campaign meant the ships would never be built.

Just before the start of the 20th century, Germany embarked on a naval expansion to challenge British control of the seas, under the direction of Vizeadmiral (Vice Admiral) Alfred von Tirpitz.

Another faction in the naval command, led by Admiral Eduard von Capelle, the State Secretary of the Reichsmarineamt (RMA—Imperial Navy Office), opposed the idea and favored traditional, differentiated capital ship designs.

The proposals were submitted to the naval command in January 1918; Wilhelm II continued to stress the importance of the "Einheitsschiff" concept and he suggested that the speed of the design might be significantly increased by removing the forward superfiring turret and the submerged torpedo tubes.

For his part, Scheer asked whether triple or quadruple turrets might be used to save enough weight for speed to be increased to 30 knots (56 km/h; 35 mph), which delayed completion of the design until mid-1918.

By that time, the studies that had been completed suggested that the weight savings would be minimal and that the more crowded triple or quadruple turrets would reduce the rate of fire too much.

[3] Two more proposals were completed in mid-1918; the first was almost the same as the L 20e α variant and the second was similar but had only six main battery guns and a top speed of 28 knots (52 km/h; 32 mph).

[13][a] The ships were never built, primarily because the shipyard capacity available that late in the war had largely been diverted to support the U-boat campaign.

Krupp, the firm that had been awarded the contract to conduct the testing, informed the RMA that design work on the new turret would have to wait and Capelle accepted the news without much objection.

The RMA filed a report dated 1 February 1918, which stated that capital ship construction had stopped, primarily due to the shifting priorities to the U-boat war.

[13] Though the ships of the class were never built, the naval historian Timothy Mulligan notes that with "the unresolved dilemma of conflicting design concepts and overly ambitious demands in battleship characteristics ..." that the L 20 α design represented, "... the Imperial Navy bequeathed a dubious legacy to its successors".

The ships were intended to have the typical single tripod foremast mounted atop the large, forward superstructure and a lighter pole main mast aft of the funnel.

The estimated muzzle velocity was 800 meters per second (2,600 ft/s)[7] The ships were to have been armed with a secondary battery of twelve 15 cm (5.9 in) SK L/45 guns mounted in casemates in the main deck around the superstructure.

[16] Directly above the main belt was a 250 mm thick strake of armor plating which extended up to the upper deck.