St. Ludwig ("St Louis") is the main Catholic church in the town of Celle in the German state of Lower Saxony. It was consecrated in 1838 and was the third catholic parish church of the new diocese of Hildesheim which was authorised by papal bull and was outside of the former bishopric of Hildesheim and Archbishopric of Mainz. It followed in the footsteps of the first two churches: St Clemens in Hanover and St Michael in Göttingen.