Karlstetten is a community in the district of Sankt Pölten-Land in the Austrian state of Lower Austria.

Karlstetten is located in the Mostviertel in Lower Austria at the south-east border of the Dunkelsteinerwald.

Cadastral communities are: Karlstetten, Heitzing, Hausenbach, Weyersdorf, Lauterbach, Obermamau, Untermamau, Schaubing.

Mayor of the community is Anton Fischer, his substitute is Josef Hofbauer.

(March 2005) The soccer team "SV Karlstetten/Neidling" plays in the "Gebietsliga West".