Erwin Alois Robert Leder (born 30 July 1951 in St. Pölten, Lower Austria, Austria) is an Austrian actor. He is best known for his role as Chief Mechanic Johann in Das Boot, a 1981 feature film directed by Wolfgang Petersen about a mission of one World War II U-boat and its crew. Johann is obsessed with a near-fetish love for the U96's powerful engines, and his nickname is Das Gespenst (The Ghost). When the sub is forced to dive deep to escape their pursuers, causing bolts in the pressure hull to fail and shoot off, Johann has a mental breakdown and has to be restrained. He is able to redeem himself by valiantly working to stop water leaks when the boat is trapped in Gibraltar.

In 2003, Leder appeared as the lycan scientist Singe in the gothic horror/action film Underworld. He reprised his role in the sequel in a brief cameo as a corpse.