The Plochingen–Immendingen railway is a main-line railway line in the German state of Baden-Württemberg. It runs from Plochingen via Horb am Neckar to Immendingen, following the upper reaches of the Neckar from Plochingen to Neckartailfingen and from Kirchentellinsfurt to Rottweil, and finally the Danube from Tuttlingen to the end of the line. It was therefore also historically known as the Obere Neckarbahn or the Obere Neckartalbahn. The Rottweil-Immendingen section used to be called the Obere Donaubahn or Obere Donautalbahn.

Plochingen is a town in the district of Esslingen in Baden-Württemberg in southern Germany. It lies on the river Neckar, on which it has a river port. With about 14,000 inhabitants, it is part of the Stuttgart Metropolitan Region.