TT-Line GmbH is a shipping company based in Lübeck, Germany, which has been providing ferry service between Travemünde in Schleswig-Holstein and Trelleborg in southern Sweden since 1962.

Since 1992, it has also operated a service from Rostock to Trelleborg (until 1997 marketed as TR-Line) and from Swinoujscie in Poland.

In 1978, TT-Line acquired 50% of Olau Line and purchased the rest of the company in 1979.

TT-Line remained the sole owner of Olau Line until the line's closure in 1994.

The company is ultimately owned by the German business profiles Bernard Termühlen and Arend Oetker through the holding company Trampschiffahrt GmbH & Co. KG.