Andreas Althamer (also Andreas Altheimer) (c. 1500 – c. 1539) was a German humanist and Lutheran reformer. He was born in Brenz. He studied at the universities of Leipzig and Tübingen. After completing his studies, he became a schoolteacher in Halle (Saale), Schwäbisch Hall and Reutlingen. In 1524, he was a priest in Schwäbisch Gmünd, where he tried to introduce the Reformation. He met with resistance from the Gmünder Council.

In 1525, in order to escape persecution due to his Lutheran leanings, he fled to the University of Wittenberg. He took a degree in theology and became a student of Martin Luther.

He was the first to write a catechism in 1528 that actually carried that title "on the cover", a year before Luther wrote his own.

As a deacon in the Sebalduskirche in Nürnberg, he took part in the Bern Disputation of 1528. In May, on the recommendation of Lazarus Spengler, he was appointed pastor to the city of Ansbach by George the Pious .

He died in Ansbach.

• Friedrich Wilhelm Bautz (1975). "Althamer, Andreas". In Bautz, Friedrich Wilhelm (ed.). Biographisch-Bibliographisches Kirchenlexikon (BBKL) (in German). Vol. 1. Hamm: Bautz. cols. 129–130. ISBN 3-88309-013-1.
• Hermann Ehmer: Andreas Althamer und die gescheiterte Reformation in Schwäbisch Gmünd. In: Blätter für württembergische Kirchengeschichte 78 (1978), S. 46-72 (grundlegend)
• Julius Hartmann (1875), "Althamer, Andreas", Allgemeine Deutsche Biographie (in German), vol. 1, Leipzig: Duncker & Humblot, pp. 365–366
• Henry Eyster Jacobs, Lutheran Cyclopedia p. 10, "Andrew Althamer"
• Heinz Scheible: Melanchthons Briefwechsel Personen Band 11
• Karl Schornbaum (1953), "Althamer, Andreas", Neue Deutsche Biographie (in German), vol. 1, Berlin: Duncker & Humblot, pp. 219–219
• Realenzyklopädie für protestantische Theologie und Kirche Band 1, Seite 413
• Robert Stupperich: "Reformatorenlexikon". Verlagshaus Gerd Mohn Gütersloh 1984, ISBN 3-579-00123-X