Unterwellenborn is a municipality in the district Saalfeld-Rudolstadt, in Thuringia, Germany.

It was created on 1 February 2006 by fusion of the municipalities Birkigt [de], Goßwitz, Könitz, Lausnitz bei Pößneck and Unterwellenborn itself which had cooperated earlier as Verwaltungsgemeinschaft Unterwellenborn.

Already on 9 April 1994, the municipalities Dorfkulm, Langenschade and Oberwellenborn had become part of the municipality of Unterwellenborn.

In July 2018 the former municipality of Kamsdorf was merged into Unterwellenborn.

This Saalfeld-Rudolstadt location article is a stub.