Theodoric IV Landgrave of Lusatia also called in German Diezmann or Dietrich III (c. 1260 – probably 10 December 1307 in Leipzig) was a member of the House of Wettin. He was Margrave of Lusatia from 1291 to 1303. He was also Margrave of Osterland from 1291 until his death and Landgrave of Thuringia as Dietrich I from 1298 until his death.
