Oflag XII-B

{{Short description|German WWII POW camp in Mainz}}

{{Infobox military installation

|name = Oflag XII-B

|native_name =

|partof =

|location = Mainz, Rhineland-Palatinate

|image = File:Zitadelle MZ.jpg

|caption = Mainzer Zitadelle, 2005

|map_type = Germany 1937

|coordinates = {{coord|49.99344|8.27422|type:landmark_region:DE-RP|display=inline}}

|map_size =

|map_alt = Mainz, Germany (pre-war borders, 1937)

|map_caption = Mainz, Germany (pre-war borders, 1937)

|type = Prisoner-of-war camp

|code =

|built =

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|used = 1940{{spaced ndash}}1942

|demolished =

|condition =

|ownership =

|open_to_public =

|controlledby = {{flag|Nazi Germany}}

|garrison =

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}}

[[File:Lieutenant(Art) Louis Fauvarque-Oflag XII B Hadamar-mars1943-Chambrée.jpg|thumb|Aquarelle par Louis Fauvarque, lieutenant artilleur français : sa chambrée dans l’OFLAG XII B à Hadamar (peinte en mars 1943 et envoyée à sa famille).

Watercolour by Louis Fauvarque, French artillery lieutenant: his room in OFLAG XII B at Hadamar (painted in March 1943 and sent to his family)]]

Oflag XII-B was a German World War II prisoner-of-war camp for officers (Offizierlager) located in the citadel of Mainz, in western Germany. The fortress had also served as an Oflag in World War I.