Theodor "Theo" Claassen (24 May 1922 – 7 September 1986) was a highly decorated Leutnant in the Wehrmacht during World War II. He was also a recipient of the Knight's Cross of the Iron Cross. The Knight's Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership. Theo Claassen was captured by American forces during the Battle for Brest and was held until 1946.