The 21st Infantry Division was a German military unit which fought during World War II.

As this was a direct breach of the terms of the Treaty of Versailles, its existence was initially concealed; it was formally designated as the 21st Infantry Division in October 1935.

Its East Prussian origin informed the adoption of the divisional symbol, a figure holding a shield bearing the black cross of the Teutonic Knights.

Along with the bulk of Fourth Army it was encircled and largely destroyed in the Heiligenbeil pocket in the closing weeks of the war.

Remnants of the division's forces were transported over the Frisches Haff to Pillau and Samland, where the unit was eventually dispersed in battle with Soviet troops, while some elements escaped along the Frische Nehrung to Hela and eventually by sea to Schleswig-Holstein.