The 2005–06 Regionalliga season was the twelfth season of the Regionalliga at tier three of the German football league system.
It was contested in two geographical divisions with eighteen teams in the south and nineteen in the north.
The champions, Rot-Weiss Essen and FC Augsburg, and the runners-up, FC Carl Zeiss Jena and TuS Koblenz, of every division were promoted to the 2.
4Despite being champions of Oberliga Südwest, Borussia Neunkirchen were barred from promotion.
FC Kaiserslautern II was promoted to the Regionalliga Süd.