Siegfried III von Eppstein (died 9 March 1249) was Archbishop of Mainz from 1230 to 1249.

He in 1244 granted freedom to the citizens of Mainz, who subsequently could run their affairs more independently though their own council;[2][3] in law it remained an episcopal city.

[4] He acted as regent for Conrad IV of Germany, while Emperor Frederick II was campaigning in Italy, 1237 to 1242.

[7] He added Lorsch Abbey to the archbishopric.

This article about a German Catholic bishop or archbishop is a stub.