The Aper Tief is a stream in Lower Saxony, Germany.

It flows through the municipalities of Apen (district of Ammerland) and Detern in the collective municipality of Jümme (district of Leer). It begins west of Apen at the confluence of the Große Süderbäke and the Große Norderbäke, runs roughly east–west and empties south of the municipality of Detern into the Jümme. Including its source river Große Süderbäke, its total length is 31.4 km (19.5 mi). The Aper Tief is tidal. Its tidal range is about three quarters of a metre.

• List of rivers of Lower Saxony

• Dipl.-Ing. Richard Eckhoff, Hilke Hinrichs: Das Aper Tief darf wieder das Bett verlassen. In: gewässer-info, Nr. 53, January 2012, pp. 569–571 (pdf file, 3.2 MB)

• Naturschutzgebiet „Aper Tief“ beim Niedersächsischen Landesbetrieb für Wasserwirtschaft, Küsten- und Naturschutz